Contents
Don't Fix It In The Mix
All About Microphones and Miking
How to Record Vocals
How to Mic a Drum Kit
Microphone Primer
Directional Response of Microphones
Frequency Response of Microphones
Transient Response of Microphones
Amplitude and Frequency
Phase Relationships
Phase and Mic Placement
Stereo Miking Techniques
Tracking Bass and Drums
Instrument Miking Techniques
Recording Piano
Recording Bass
Live Sound Primer (or making lemonade)
Recording Vocals
Recording Horns
Recording Drums: The Foundation
Recording Drums: Choosing Microphones
Recording Drums: Microphone Placement
Recording Drums: EQ and Track Sheets
Recording Electric Bass
Advanced Drum Tuning
Balanced vs. Unbalanced Audio Connnections
Setting Up Gates and Compressors
Console EQ
Advanced EQ
Production Tips Part 1 (punch-in/out techniques)
Production Tips Part 2 (pitch shifting)
Project Diary Part 3 (some live recording)
Project Diary Part 10 (fixing some parts with Pro Tools and flying in background vocals)
Project Diary Part 11 (background vocal recording techniques)
Project Diary Part 12 (vocal production techniques)
Mixing Part 8 (drum mixing)
Mixing Part 9 (polishing a rough mix to perfection)
Mixing Part 10 (EQ and Compression)
Phantom Power Demystified
Recording the Voice
Advanced Dynamics
Inside a Session: Tracking
Frequency and Pitch
How To Get Great Drum Sounds From Your Home Studio
Practical Drum Kit Miking: Part 1
How to Record a Kick Drum
Three mics on a drum kit?
Guitar Miking: Getting a Great Guitar Sound
Equalization Artifiacts
Equalization Applications
by Zach Ziskin
One comment I often get from bands and artists I work with is how relatively quickly I am able to get mixes sounding great. I always tell them that mixing is easy when you're working with great sounds to begin with. A well worn cliche in the recording world is to 'fix it in the mix,' or gloss over inadequacies and mistakes during recording in favor of doing repair work during the mixing stage. Sure, it's possible to take mediocre sounding tracks, and with some 'massaging' and studio wizardry produce a cohesive and satisfying final mix, but the extra time and effort spent doing so is much better spent before the first note is played.
When I'm tracking a project, the first thing I do before I even go to the mic cabinet is spend some time checking out the instrument itself. One of the most common 'problem instruments' to get to sound good is a drum kit. Drum tuning is the single biggest reason drum tracks either sound great or awful. I never cease to be surprised by how many drummers don't have a clue how to properly tune their drums, or set them up for recording. Many drummers simply bring their kit into the studio with old, improperly tuned heads, cymbals set up a hair above their toms, and miscellaneous hardware creaks and squeaks. Fortunately, I know a drum tech who is available for session setups, and in a half hour has a formerly awful sounding kit ready for any recording.
When a drum kit is optimally tuned and set up, it almost doesn't matter what mics you use. I've worked many times with the same drummer who is a pro at tuning, and most of the time I simply end up throwing SM-57's on all his drums, including the kick, and with relatively little adjustment of the mic placement. The tracks sound amazing. If your drummer isn't well versed in tuning, I highly recommend budgeting the $75 or so to have a knowledgeable drummer or tech come in and tune up the kit. It will be money well spent.
Bass is another instrument that can be tricky if care isn't taken with the setup. The bass needs to anchor the low end and, along with the kick drum, form the bedrock that the rest of the tracks sit upon. The most common way to record bass is DI, or by plugging the bass directly into the console or computer. Whereas with drums it is preferable to use new heads, with bass I find new strings to be too bright and prone to excessive 'finger noise.' I prefer a bass that has strings that have been on and played for at least a couple of days. That way, the strings still have lots of punch and sustain, but don't have any of the buzz and noise. After all, you don't need the bass occupying any of the higher frequencies--you'll need those for your guitars, vocals, etc.
An important note regarding the bass--the sound of the bass should be listened to in conjunction with the drums. It's no use getting a great bass sound by itself that doesn't gel with the drums you've tracked. It's important to experiment with the tone knobs and/or pickup selections on the bass to find the tone that gels with the drums best. Even better is if you can borrow a couple of extra basses from some other bands or friends to audition during recording.
Electric guitar is especially crucial to get right before you break out the microphone. Since an SM-57 placed right in front of the amp's speaker is the norm for guitar recording (and has always worked great for me), the bulk of the tweaking takes place with the guitar itself, amp settings, and signal routing to the amp. To get good clean tones, make sure that the guitar you're using has been properly set up in terms of pickup height and string height. If the height of the individual strings is different over a pickup, some notes will sound loud and clear while others get lost. Again, for those who aren't well versed in guitar setups, a trip to a reputable guitar tech or luthier can do wonders for your sound.
Getting good distorted or overdriven guitar sounds requires more attention to the amplifier and pedals (if used). The key to good distorted sounds is compression, which you should look to get in one of two ways. If you are getting your distortion or overdrive from the amp itself, it's best to crank the volume up as much as possible, so that the output tubes begin to saturate (assuming you're using a tube amplifier--for those using solid state amps this doesn't apply). This will create a natural compression of the signal and balance the overall sound. If on the other hand you're using a pedal for your distorted tones, amp volume isn't as much of a consideration, as most distortion/overdrive pedals provide a healthy dose of compression to the signal. In fact, in these cases it may actually be preferable to record the amp at a relatively low volume. For instance, it is widely reported that the Edge from U2 records most of his tracks through small amps at low volumes, using various distortion pedals.
When it comes to recording acoustic guitars, again it all comes down to a great sounding source. Many cheaper acoustic guitars have low end 'bumps' that make for uneven and boomy patches when played and recorded. A well balanced acoustic guitar that is smooth from low end to high will record well with just about any decent condenser mic put in front of it. Some of the better names include Taylor, Gibson, and Martin.
One part of the recording discussion that needs to be addressed is the performances by the musicians themselves. You can have the best drum sound or bass setup, but it won't matter if the drummer's hitting is inconsistent and meter deficient, or the bassist is sloppy and overplays. Part of being a good engineer sometimes involves making suggestions to the musicians on how to best perform their parts (in the absence of a producer). By spending the extra time up front to make sure that the players' instruments and performances are as top notch as possible, you assure yourself of an easier time during mixing, and a professional sounding final product.
In future articles I will discuss specifics on tracking, from microphone selection and placement, to eq considerations and compression, as well as in depth discussions on mixing.
In my previous article I discussed the importance of working with the instruments themselves to maximize the sonic quality of the recordings. In the next two installments, we will discuss miking, including selection and placement, citing some of the microphones most commonly used in major recording sessions.
Assuming that the instrument or sound we are recording sounds the way we want it to when listening to it live in the room, the goal of proper miking is to get the microphone(s) to 'hear' it the same way and basically translate those sounds as faithfully as possible. The range of quality and cost of various microphones is almost endless, and which mics you choose (or are limited to by budget and availability) will determine how faithfully your sounds can be captured. For instance, if you put a $75 dynamic mic and a $3000 condenser mic in front of the same acoustic guitar, both will get the basic character and tone of the instrument. However, the $3000 mic will have a clarity and transparency to the sound and be well balanced throughout the EQ curve, while the $75 mic will have not translated certain frequencies and may sound one dimensional or boxy.
There are two major types of microphones--dynamic and condenser (there is a third major type called ribbon microphones, but they are so expensive that if you own these, you probably don't need to read an article on microphones! ;-)). Dynamic mics are rugged and don't require external power. These can be plugged directly into a console or line mixer and produce sound. Because of their sturdy and rugged nature, dynamic microphones are ideal for very loud sound sources such as close miked drums and guitar amplifiers. Condenser microphones are more delicate and require an external power source, commonly referred to as phantom power. Most modern mixers and consoles provide phantom power for the mic inputs in the form of a +48V button or switch. If you don't have one, you'll need an external mic preamp or power supply equipped with phantom power. Condensers have a wider frequency range and sensitivity than dynamic mics and are well suited for sources such as vocals, strings, acoustic guitars and room and ambient sounds. Within the categories of dynamic and condenser mics there are small diaphragm and large diaphragm microphone designs. Small diaphragm mics are smaller and pick up sound in a specific area, usually sounds that the mic is pointed directly at. Large diaphragm mics are larger and tend to pick up all sound in a general area.
Aside from vocals, I prefer not to EQ or compress any tracks as they're being recorded to disk or tape. I will spend whatever time I need tweaking mic position or changing mic selection to get the EQ in the ballpark of where I want it for a track. Sometimes I will very lightly compress a kick and snare drum to optimize levels during recording if the drummer is inconsistent, but otherwise I simply run the mics into mic preamps and directly to disk/tape.
Before discussing particular miking techniques, one tool that I highly suggest you use is a great pair of headphones. The better ones cost upwards of $150 or $200, but will give you a very good reference when experimenting with mic placement out in the recording room. Ideally you will be able to plug the mic(s) into the console, turn up the volume and listen in the room to the source with the headphones and move the mics around until it sounds great in the phones. This won't be as useful when doing loud sources like drums and loud guitar amps, but works wonders when miking acoustic guitar, strings, piano and non percussive instruments.
Drums are one of the most complex instruments to mic since there are several mics, usually with dynamics on the fast, percussive parts of the kit (i.e. the drums themselves) and condensers on the ringing parts (the cymbals), and all interact together to produce an overall kit sound. Let's start with the kick. There are two common ways to mic the kick, the first being a dynamic mic inside or near the opening of the front head. As I described in the previous article, if the drummer has tuned his drums well and they sound great already, you shouldn't have much trouble getting a good sound. You might need to experiment with the angle of the mic and how far into the drum shell it is. The second method is to use two mics on the kick, one inside the kick as already described and a condenser mic a few feet in front of the kick drum. Using some heavy blankets and chairs, form a sound 'tunnel' from the kick to the condenser mic to help isolate the sound from the rest of the kit. The two mics are mixed together to form one kick drum sound. I only recommend going this route if you're having particular trouble getting a good kick sound with just the one mic inside the kick drum. Some of the common mics used on kicks include AKG D-112, Shure SM-57, and my personal favorite is a Shure Beta 91, a relatively new mic (and a condenser), but amazing in its ability to just drop inside a kick drum and instantly sound great.
Toms are miked usually with dynamic mics, most commonly Shure SM-57's or Sennheiser 421's positioned 2-3" over the top head of the drum. Again, while some tweaking of mic position may be necessary, well tuned toms should sound great with the mics in a general position over them. Snare drum is usually also miked with a Shure SM-57, but can be trickier, since snare mics will commonly pick up bleed from the hi hat. There are a couple of techniques to help minimize this. First is to position the mic so that it is pointed away from the hi hat and in the direction of the floor tom. Angle it slightly down toward the top of the snare. The second technique, which can be used in conjunction with the mic position, is to mount a 'mini gobo' on a mic stand and position in between the snare and hi hat, effectively isolating the snare mic. I use a 5" x 7" piece of drywall covered with carpet for this purpose.
The hi hat will usually be miked with a small diaphragm condenser pointed at an angle toward the outside of the hat. If the mic you use has a high pass filter on it, it's probably a good idea to put it on, as you won't need any low end on the hi hat. Some common condenser mics used on hi hat are Shure SM-81, AKG 451 and 414 and Neumann KM 184.
The overheads, along with the kick drum represent in my opinion the most important mics for the drum kit. In fact, if I were given only three tracks for drums, these would be the three mics that I would set up. Well placed overhead mics can make up more than 70 percent of the overall drum sound, with the other drum tracks used to provide extra definition and impact to the individual drums. The overhead mics should be placed well above the whole kit, usually anywhere from 3 to 5 feet above the kit. There are a couple of ways to position the overhead mics. The first, which will be the route you'll go if using large diaphragm mics, is to place one mic over each side of the kit, pointing down and slightly away from each other and toward the cymbals. Here is a little secret that will help your positioning to maximize the sound of the snare in the overheads. Measure the distance from the center of the snare to the capsule of the left overhead mic, and then match the distance to the capsule of the right overhead mic. This will also solve many phase problems associated with stereo mic setups. Commonly used large diaphragm mics for overheads include Neumann U87's, Audio Technica 4050's and AKG 414's.
The second method for overheads involves using small diaphragm condenser mics in what's known as an X-Y configuration. Both mics are positioned in the same location above the drum kit, but criss crossed so that each is pointing down to the opposite side of the kit. This provides a very wide stereo image, often wider than the first overhead technique. Small diaphragm condensers could also be used with the first overhead technique, but produce better results for the overall kit sound in an X-Y setup. Commonly used mics for this setup include Neumann KM 184's, Shure SM-81's, and Audix makes some great new mics in its SCX series.
Finally for drums, and optionally based upon the number of tracks you have available, are room mics. These can be great to add natural ambience and reverb to a drum sound, or get that massive 'John Bonham' sound. If you have a decent live sounding room, setting up a pair of large diaphragm condensers at human ear level anywhere up to 20 feet away from the kit can give you another dimension to the drum tracks. Mic choices for room tracks are often the same as those listed for overheads.
In part two of the discussion on miking we'll cover other commonly recorded instruments, including guitars, bass, voice, piano, horns and strings.
Now that we've discussed the various types of microphones and their uses, let's continue with descriptions of the commonly recorded instruments, how to mic them and commonly used mics, and in this installment I have some audio samples to aid in the discussion.
In the last article I described miking drums. Here is a raw audio sample of a drum kit I recently recorded. The snare and toms were miked with Shure SM-57's, the kick with an AKG D-112, the hi hat with an Audio Technica 4033 and the overheads with Shure SM-81's in an X-Y pattern. There was no compression or EQ used on any of the mics going to disk, and I didn't even end up moving any of the mics after I placed them. Hopefully this will help drive home the point that above all else, the actual sound of the instrument you're recording will determine how good your tracks sound.
We'll begin this month's discussion with acoustic guitar, which moreso than most instruments will vary in its sound by moving the microphone even a fraction of an inch. Acoustic guitars have a wide range of EQ at the various locations on the instrument. In front of the soundhole, the guitar sounds boomy. Toward the bridge is mellower and thinner. The best overall spot for most applications is where the neck meets the body of the guitar, where it's not too boomy and has good top end. In almost every miking situation for acoustic guitar you'll want to use a condenser mic, preferably with a large diaphragm to capture all the transients and high end definition. If the mic has a high pass filter, switch it in, as it will filter out a lot of undesirable low end boominess and rumble. If using just one mic on the acoustic, place it somewhere between 5-12" away from the guitar pointed at the neck/body joint. Again, as previously mentioned, listening with a pair of quality headphones while placing the mic will help, as moving the mic just fractionally will change the sound and EQ, and you can hear the changes as you do them.
Another option for acoustic guitar if you have it is to use two mics on the guitar, one placed as described and the second another foot or two behind the first mic pointed at the guitar. With just the first mic, you'll get a very tight, 'in your face' sound. The second more distant mic will give you more ambiance and 'space' to the sound. By blending the two mics together either to tape or recording both and blending in the mix, you'll get a more natural sound with a little more air to it. Click here to hear an acoustic guitar I recorded with just one mic, and here to listen to the same guitar with two mics. For those interested, the guitar was a Taylor 310CE close miked with an Audio Technica 4033 and distant miked with an Oktava large diaphragm condenser. Common choices for recording acoustic guitar include Neumann large diaphragm condensers such as the 103, 87, etc., AKG 414, and Audio Technica large diaphragm condensers.
When it comes to electric guitar, the standard has been and still is a dynamic mic close miked on an amp. While there can be some variance in the EQ by tweaking the mic position off center of the speaker cone, for the most part the sound and quality of the track will be determined by how good the amp and guitar sound by themselves. Some engineers also like to distant mic an amp and blend the two mics as described with the acoustic guitar, and some engineers who have access to high end ribbon mics will use them on amps to great effect. I personally have found that I can get most of the sounds I want with the one close mic and by tweaking the amp and effects. Commonly used dynamics include Shure SM57 and Sennheiser 421.
Piano is a fairly easy instrument to mic as long as you have a well set up and tuned piano to work with. For the purposes of this discussion we'll deal with miking a grand piano (or baby grand). Piano is most commonly recorded in stereo with two mics, one capturing the upper musical range and the other the lower, and with the piano lid propped open. For those who haven't seen what the inside of a grand piano looks like, here's a picture. As you can see, there are two groups of strings that criss cross in different directions. The group of strings on the left are for the low keys and the ones on the right are the high keys. So a common way to mic the piano is to place a condenser mic (I've seen both large and small diaphragms used here) 8-10" above the upper strings (the right side in the picture) closer to the keyboard end of the piano. The second mic (usually a large diaphragm condenser) is placed above the lower strings toward the back of the piano. The first mic track is panned hard right and the second hard left, so that as the player plays from the low notes to the highs, the sound moves across the stereo field from left to right. I rarely use any EQ or compression when recording the piano, as good condenser mics on a well balanced piano should produce a great sound by itself. Commonly used condensers include the usual suspects, the Neumann's, the Audio Technicas, and the AKG's.
Vocals are pretty straightforward to record--you set up the mic, stick the singer in front of it and go, right? Well, sort of. This is the one place where you can't just try different instruments if you don't like the timbre and sound, after all that would mean getting a different singer! Therefore, more than any other instrument, having a selection of mics to choose from is essential. Some singers have a very cutting, midrangey quality, where a smooth mic such as a Neumann U87 would work great. Others singers are very full and booming, where a more transparent and top end emphasized mic like an Audio Technica 4033 could be called for. This is also the one area of tracking where I will use a compressor going to tape/disk, as most singers can be very dynamic volume-wise. Again, the standard selection of mics for recording vocals comes from the large diaphragm condenser family.
Strings and horns are lots of fun to record, simply because you don't get to work with them as often as other commonly recorded instruments, and because listening to the sound of good string and horn players is so wonderful. With strings, how large a string section you're working with and what kind of string sound you want will dictate how to mic them. If you're recording a full 18 piece string section and are going for a lush 'pad' type of sound, you can probably get all that you need from 4 room overhead mics placed several feet above the players. If recording a smaller ensemble such as a quartet, you'll probably want to individually mic the players with condenser mics. Individually miking will also give you a much more up front and intimate sound, where you'll be able to hear the horsehairs of the bows drawing across the strings (check out the Beatles' 'Yesterday' or 'Eleanor Rigby' for examples of this). For cellists, usually a large diaphragm condenser mic placed several inches in front of the cello pointing toward the 'F' holes or bridge will produce a nice sound. For viola and violin, either a small or large diaphragm condenser placed a foot or so above the instrument pointing down toward the F holes works well. Click here to listen to a recent string session I did with one violinist and cellist double tracked to sound like a quartet. The cello was miked with an Audio Technica 4033 and the violin with a Neumann TLM 103 through mic preamps straight to disk.
Horns, including saxophones, trumpets, trombones, and french horns can be miked with either dynamic or condenser microphones as horns tend to be quite loud and provide plenty of volume for the mics to handle. If using dynamic mics, such as Sennheiser 421's or 441's, you can position the mics closer to the bell of the horn for a tighter, more up front sound. With condensers, you should keep them anywhere from 6-12" away from the bell so they don't get overloaded, and in fact you may still need to switch in a pad on the mic if it has one. Again the common choices for horn condenser mics include AKG 414, Neumann U47, U87 and TLM series, and Audio Technica's AT series.
If you've noticed many of the same mics popping up in this discussion from one miking application to another, it's no coincidence. High quality microphones are usually well suited for many applications. The great news for semi-pro and home recordists is that prices continue to come down for great mics, and newer, high quality mics are coming to market for less and less money. To wrap up this discussion on microphones and miking, I'll recap a few mics I consider to be some of the best, most versatile and affordable microphones, both condenser and dynamic that any engineer should consider having in their arsenal and current price ranges they can be found for on ebay as of this writing:
($200-250)- Amazing large diaphragm mic for the price. At these prices, get two for stereo applications.
[Shure SM57?] ($60-75)- The industry standard mic for snare drums, toms and guitar amps.
Sennheiser 421 ($200-300)- High end dynamic mic commonly used on drums, horns and guitar amps.
($520-600)- Any Neumann is a good Neumann, and this model is one of their most affordable high quality large diaphragm condenser mics around.
($550-600)- A longtime industry standard for everything from acoustic guitars to horns to vocals and more.
($200-250) -Great small diaphragm condenser mic for drum overheads, hi hat, strings, and piano.
Of course there are plenty of other amazing affordable mics on the market today, and your needs and budget will dictate your selections. Happy recording!
Difficulty Level: Easy Time Required: 30 minutes
Here's How:
Tips:
Related Features:
Difficulty Level: Easy Time Required: 30 minutes
Here's How:
Difficulty Level: moderate Time Required: under 1 hour
Here's How:
Tips:
Related Features:
A microphone is a transducer. It changes one kind of energy into another. As a comparison, the human body has two transducers: the ears and the voice box. What you need to know about microphones can be broken down into the following word: TRAP. Each letter of 'TRAP' stands for a mic attribute or a fact that you should know about mics in general.
T -- Type - Studio mics
break down into two basic types. Dynamic and Condenser. Dynamic mics work
on the principle of magnetic induction. They need no external power to run
and are very simple to make and relatively cheap to buy. Dynamic mics come
in two varieties: Moving coil and Ribbon. Moving coil mics use a magnet,
a coil wrapped with wire and a diaphragm that sits over the top of both.
Sound pressure hits the diaphragm and moves the coil across the magnet.
This creates the voltage that travels out and along the mic cable on the
way to the mic
pre-amp. A ribbon mic is a bit different. Instead of a coil and diaphragm,
a thin metal corrugated ribbon is stretched across the magnetic field. Sound
pressure hits the ribbon and moves it across the magnet. Both these mics
have their own particular characteristics dealing with frequency
and transient
response.
Condenser mics are generally more expensive and have a flatter frequency
response than dynamic mics. They also operate in an entirely different fashion.
For one thing, these mics need power to run. This is called phantom
power and is +48Vdc. Phantom power comes down the mic cable from the
console, a battery inside the mic or standalone power pack. The phantom
power charges a capacitor which holds a charge in the mics' fixed backplate.
In front of the backplate resides a thin diaphragm. When the diaphragm moves
in relation to the fixed backplate, a charge is developed in relation to
how much movement the diaphragm makes. Unlike the signal created by the
dynamic mic, a condenser's signal is very weak and must be amplified before
it gets to the console. In order to do this the mic contains a small amplifier
that boosts the signal before it leaves the mic.
R-- Recognition - To run a session successfully in a studio environment that may have an extensive collection, you need to know your tools. Just as a plumber or a carpenter could tell you what their tools are. To accomplish this, you must study mics in general, ask questions and do a lot of reading on the subject. This site has extensive info, including quizzes about mics. Use the search engine at the top of any page on my site or the feature index to find more information.
A -- Application - What mic is good for what job? Do you know the best mic for recording kick drum? How about vocals or horns? Once again, study is the key. Do your homework and you'll soon have a bag of tricks that will serve you well in the studio.
P -- Patterns - The directional response of a mic has to do with how the mic picks up sound around it's polar axis. The front of a mic is called on-axis, all other directions into the mic are called off-axis. When you talk about the on-axis and off-axis response, you are talking about how a mic picks up sound in reference to those directions. There are five basic polar patterns that mics offer. Omni, Cardioid, Hyper-cardioid, Super-cardioid and Figure eight. Read the next few features for further explanations on these patterns and how they effect what you're recording. (18.3.1997)
Every mic, by design, has a pattern in which it picks up sound. This is called the mics directional response. This response is represented in one dimension using a polar pattern diagram like the drawings below. However, in actuality the mic picks up sound in 360 degrees. There are five basic patterns that we will discuss here, some common and some not so common.
One of the most
common patterns is Omni. Think of this like a giant beach ball with the
mic placed at the center. The mic picks up sound in a 360 degree arc. As
you can see in the drawing, 0° (on-axis) and 180°,270°,and 90°
(off-axis) pick up sound equally. When placed properly in pairs, mics with
this pattern present a very real representation of stereo. Other patterns
in pairs can present sometimes negative characteristics involving phase
and what's called proximity effect. Omnis do not have these problems(phase
and other waveform properties will be discussed in an upcoming feature).
The next pattern is called cardioid. You can see where it got its
name because it is in the shape of a heart. The drawing shows that on-axis
response is full and as you come around the side to the back of the mic,
response (volume) is diminished. This pattern is said to be uni-directional
or directional. It works best in a situation where you want the off axis
signal to be diminished. For instance, when you're miking a snare drum or
toms on a drum kit you'd want to downplay the off-axis signal which would
be the cymbals, hi-hat etc.
Cardioid now
slowly morphs into bi-directional with two stops along the way. Super-cardioid,
as you can see, is very much like cardioid with a few changes. The front
lobe starts becoming more directional. In other words it shrinks at the
sides. This pattern also starts developing a small back lobe so it is letting
in a little bit of sound off-axis.
Hyper-cardioid
is the above and more so. The front lobe becomes even more directional and
you can see that the back lobe is even more pronounced. This pattern would
be good for a situation where you want the mic to be more directional and
also want to pick up more of the environment that you're recording in. For
instance, when recording a choir in a nice concert hall you could 'aim'
the mics at the choir and also get some of the nice off-axis signal that
would bring in the sound from the rear of the mic. Keep in mind, Hyper-
and Super-cardioid let in less off-axis from the sides of the mic so they
are great stage mics for live applications.
Last stop is
bi-directional or figure 8 pattern. This pattern picks up equally well on-
and off-axis and cancels at 90° and 270°. You could, for instance
have two vocalists, one at either axis and pick them both up equally well.
Don't confuse this pattern with a stereo mic. The signal still comes out
of the mic in mono, you're just able to pick up the sound in a figure 8
pattern. Bi-directional is limited in it's usage, 90% percent of the time
omni and cardioid will be your patterns of choice. As you'll see in future
features, this mic can be used effectively in a M-S
miking application.
Some mics have fixed patterns; dynamic mics are always fixed for instance. Condensers sometimes have the ability to switch patterns. As we will find out in future features (say THAT ten times!), these patterns each have their own specific situations where they excel. Stay tuned for more info that can improve your recordings. (25.3.1997)
A frequency response chart tells you what a microphone puts out as opposed to what it gets in and can give you some valuable clues for targeting its usage. It is simply a visual representation of what parts of the mic's bandwidth is boosted, cut or not there at all.
How Is It Measured?
Frequency response charts are generated at the factory by testing the mics in an anechoic chamber. This is a specially constructed room just for audio testing. The room is completely dead, without any sound reflection. A speaker is set up in front of the mic that is being tested and pink noise is played (pink noise is all frequencies with equal energy in every octave). The mic is routed into a spectrum analyzer that measures the output. A frequency response chart is produced from this, usually over the 20 Hz to 20 kHz range which is the range of human hearing. Like any manufacturing process, no two mics are exactly the same; you can even get an occasional lemon. This chart helps the manufacturer keep quality control high and lets them match two mics for sale as a pair. As engineers, we can look at the frequency response chart and get a ballpark estimate as to what the mic's all about. In a perfect world, a flat frequency response is the golden mean. In other words if the mic is putting out exactly what it gets in then that's great! However, last time I checked, this world isn't perfect and all mics have some kind of variance from the zero line. This shows up as dips and peaks on the frequency response chart. These peaks (called bumps) and valleys are not spikes but gradual rises and falls. Condenser mics usually stray little from the zero line, whereas dynamic mics response can look like a mountain range .
The Real Difference
A lot of factors determine what makes up a microphone's frequency response, for the most part you can think of condensers as being more true to life than dynamics. This also accounts for the great price difference in the two mics. You can get a brand new dynamic for under $100, whereas a decent condenser starts at around $400 and then the sky's the limit. For instance, a refurbished U-47 tube mic can be as much as $7,000! Does this mean that a dynamic is not desirable at all? No way! There are many applications where you'd prefer to use a dynamic mic. For instance, dynamics can take more level in general and great for use in high SPL (sound pressure level) situations. Close miking of drums for instance.
Let's take a workhorse mic like the Shure SM-57 and use it as an example. Look at the frequency response chart (this is a re-draw and not from the manufacturer so it's not gospel, just meant to be an estimation). You can see that at 50Hz the mic is down -10dB. It then gradually rises to zero level at about 150Hz. After that it's flat until you get to the 4KHz to 6KHz where you have a bump that rises and settles down and then the mic drops off at the high end. Definitely not a true representation of what's going on in the real world. However, this is a good thing! First off, this mic has a cardioid directional response. (See the polar patterns explained in previous features.) This means that the mic would be directional and would cancel from the back. In addition the mic is built like a rock and is cheap to buy. Looking better all the time. The frequency response makes it especially good for snare drum because the fundamental frequency of the snare resides in the 150Hz to 250Hz range, right where the mic is flat. The presence bump at 5kHz is just where the snap of the snare resides. In addition, it's rolled off low end makes it great for de-accentuating the kick drum which is very close in proximity. Lastly, the cardioid pattern makes it naturally reject the off-axis hi-hat, cymbals and toms. A match made in heaven! That's why this mic has been around for a long time and will continue to be so. At the other end, this mic would be a bad choice for miking a kick drum because of the lack of low frequency return.
A mic's frequency response chart can tell you a lot about where to use or not use a mic. We will refer to this in upcoming features and mic reviews. Stay tuned for more info along our road to better and better recording. (1.4.1997)
A transient is a short duration, high level peak, such as a hand-clap or snare drum hit. How a microphone reacts to a transient will directly effect its frequency response and how much SPL (sound pressure level) it can take. The transient response of a condenser mic, for instance, is quite accurate and quick. The design of the mic makes it very sensitive and mostly flat across a broad range of frequencies (depending on the mic of course). The diaphragm is able to snap back to a neutral position quickly and thus is ready to be hit by a new wave and react to it accurately. This is called the impulse response time. You can see in the drawing A that the transient response of a condenser mic gives you the full peak and the valley on the positive and negative side of the center line. Because of this accurate representation of the positive and negative transient, a condenser mic's headroom is quickly used up. There is a price paid for a mic that gives back most of what it gets in. The price is that it can't take a lot of SPL.
On the other hand if you look at drawing B, you see that the dynamic mics response is a bit different. It doesn't give you the full positive or negative wave. The wave is a bit clipped off at the top and bottom. Thus the headroom is not used up as quickly and as a general rule, dynamic mics can take more level than condensers. The third drawing, drawing C, shows you the transient response of a ribbon mic (also in the dynamic family). This mic gives back even less than a moving coil dynamic microphone. You can see that the positive wave has a crew-cut and the bottom or negative part of the wave is almost non-existent. This is because ribbon mics use a thin corrugated piece of metal rather than a diaphragm and a coil like it's brother. The ribbon is very thin and is only anchored at top and bottom. When a wave hits the ribbon, it goes through a lot of motion before it comes to rest. This gives ribbon mics their characteristic rounded off or smoothed out sound. Ribbons have made a recent comeback since Steve Albini used a Coles 4038 for recording the guitars on the multi-platinum effort he produced with Nirvana. The guitar sound is smooth, yet cutting and sounds great.
One exception to the idea that condensers can't take as much level as a dynamic mic is the Earthworks line of fixed omni condenser mics. These mics use an extremely small diaphragm. This results in an extremely quick impulse response time and an extended frequency response that is mostly flat up to 40k. They can also take almost nuclear sound pressure levels.
For more info on mics and preamps, visit my Subject pages on that topic. (8.4.1997)
Before we get into the specifics of mic placement and a lot of what might be foreign looking gear and situations, I think it's a good idea to lay some groundwork. These next features will deal with the basic properties of sound and how it works in our environment, which is air. These properties are not just book terms or boring edu-babble, but practical everyday things that you'll come across time and time again. Things like polarity, phase and how sound changes over time (called the envelope). We'll be tying in each concept with a real life application. So hang in there. If you're way ahead of me on this check back in a few weeks and we'll be covering the more advanced topics. Also, I just got my hands on three different mics from Equitek. The E-100, E-200 and E-300. I've never used these mics so I'm going to give them the complete once over. It will probably be featured in mid-May or so. Keep your eyes here for great stuff!
We will concentrate on two properties of sound this week. In order to study sound in one dimension we will use the drawing of a simple sine wave. A sine wave is like the tone you hear in the Emergency Broadcast System alerts. It is a pure tone with no overtones. Drawing A is a sine wave.
Amplitude
The first property of a soundwave we're going to cover is amplitude. It has to do with the distance above and below the centerline of the soundwave. The center line is the horizontal line in the drawings above, it is zero degrees. The vertical arrows in Drawing A denote amplitude. Simply stated, the larger the distance above and below the line the louder the sound. I always remember that this has to do with volume by keying in on the word AMP in amplitude. If you were a sound editor or were doing some digital editing on a DAW (digital audio workstation), you'd be dealing with an amplitude display such as this every day. The displays of most workstations show the recorded sound as a left and right complex soundwave. The left and right waves (denoting stereo) sit inside two rectangular boxes, one on top of the other. As the sound plays, the display will scroll horizontally and you will see the overall volume of the complex wave as very tightly compacted vertical lines. If the line exceeds the box it causes distortion. The display of the amplitude of the wave can tell you right away if you've exceeded the headroom of the system.
Frequency
The second property is frequency. It is measured in Hertz and has to do with how many cycles per second the wave goes through. One cycle is when the wave goes up, down through the line and back up again to the starting point. The beginning and end of a cycle is shown by numbers 1 and 2 in the drawing. This measurement can be taken anywhere in the wave as long is it ends up where it started. The numbers of times this happens in one second is the frequency of the wave. The more cycles per second the higher the sound. So frequency has to do with pitch. Every musical note, for instance, has a related hertz value. You see frequency represented on recording consoles and a lot of outboard gear. For instance, in the EQ section of some consoles you are able to sweep a band of frequencies to choose which one you want to boost or cut. Knowing how certain frequencies affect the sound of an instrument can make it easier to EQ that instrument and change its personality. This in turn can help you fit those sounds better into a mix and make it stand out more, or not. For instance, 20Hz to 100Hz provides bottom, 100Hz to 200Hz warmth, 500Hz to 1500Hz definition, 1500Hz to 4KHz Articulation, 4KHz to 10KHz Brightness and 10KHz to 20KHz air. As an engineer, frequencies are the paints you use on the canvas of sound.
Next week we cover more properties of sound and how they relate to real-life situations. Be healthy and enjoy life! (15.4.1997)
Phase has to do with the relationship of one soundwave to another. Two weeks ago (see previous feature 04/15/97), we discovered what amplitude and a cycle of a wave is. To quickly re-cap, a wave's cycle runs either above or below the centerline, then comes back through that line and loops back again to the starting point. The wave ends up traveling 360 degrees as pictured below:
If two waves have a completely opposite phase relationship, as in the
next drawing, they are said to be 180 degrees out of phase, or simply, polarity
shifted.
If the waves are equal in frequency and amplitude and 180 degrees out of phase, they will completely cancel out and the end result will be 0dB. You know from simple math that when you add equal negative and positive numbers you end up with zero. This is exactly what's happening with out of phase sounds. For every positive excursion of the wave there is an equal and opposite negative excursion. The sum of these two adds up to zero. In addition, waves can meet each other at varying degrees out of phase, 60 degrees or 100 degrees for instance. In that case, instead of canceling out, the waves will boost some frequencies and cut some others. Little Labs makes a slick product to fix this kind of problem, but it's best to use proper mic placement in the first place to keep this from happening.
Phase Trickery
Because phase relationships are always at play in the real world, they can be incorporated into products used to get rid of unwanted sound. Think back to the last time you heard a helicopter traffic report. What was missing? The sound of the helicopter was missing. If you've ever been inside a helicopter you know that it's extremely loud, too loud to carry on a conversation without yelling. Now you've got a traffic reporter with a headset mic on and he's talking in a normal tone of voice and you're understanding every word and just hearing a gentle whirring in the background. How do they do it? They use the properties of phase to help. There is some complex math and processing going on but basically, you take the headset mic, which is picking up the voice of the pilot and the ambient noise of the copter. This is fed it into a mixer which is also receiving a feed from a second mic somewhere in the cockpit. This second mic is just picking up the ambient noise in the cockpit. If you flip the polarity of one of these signals then sum them together, what do you have left? Of course, the voice is the only thing remaining because it's the only part of the sound that's not common to both mics. The ambient noise cancels and the voice doesn't; very slick. Of course there are some other things added to the equation to make this work. Powerful real-time adaptive filters are needed to constantly track the interference then account for the difference in the interference picked up by the cockpit mic and the interference picked up by the wanted signal mic.
The Good, the Bad and the (out of phase) Ugly
While out of phase signals in the previous example is a good thing and useful, out of phase signals in the studio are something that are not desirable. Not to say it can't be used creatively, but in general it's something to avoid. As an engineer, you should know, by ear, what an out of phase signal sounds like. In mono, the effect of two stereo signals being out of phase is drastic and undeniable. Whatever signals are shared by both speakers in a two channel system, like your home stereo, will disappear. Sometimes completely and sometimes not but it will sound 'wrong.' In stereo the effect is not as drastic but with a few repetitions you can hear the difference. You will hear the following things in a stereo signal that is out of phase.
To clarify, by center image I mean the effect of what's called the 'phantom image.' When you sit between the speakers, whatever is shared by both speakers, is heard in the center (that is on a system that's in the proper polarity alignment). When that same system is out of phase, that center image is gone and the sound seems to come from around the side of your head. When I say 'absense of low frequency,' I mean the things in the mix that occupy the lower end, like Kick drum, bass guitar etc. When low frequency is absent, the signal sounds very 'thin.'
Absolute and Relative Phase
If you don't have a console at home that will allow you to flip polarity, you can do a little experiment that will allow you to put your speakers out of phase and hear the effects I'm speaking of. Simply go behind one of your speakers and switch the wires from positive to negative and negative to positive. This will put one speaker out of phase and also your system. Then sit between the speakers and listen to your favorite CD. Then flip the speaker back again and compare. Notice the difference? Putting both speakers out of phase is called being Absolutely out of phase and it will sound normal to your ear. This is because both speakers are out of phase and have nothing to relate to. The other way, where only one speaker is out of phase, is called being relatively out of phase.
Because of the complexity of this week's topic, we're going to break it up into two features. Next week we'll talk about how you can stay out of phase trouble when miking anything in stereo. (29.4.1997)
When you are miking an instrument in stereo (that is, with two mics) there is a possibility that the mics could be "seeing" the signal in different phases of the wave. This is because of the location of each mic in relation to the cycle of the soundwave. This can happen when the mics are different distances from the source. For instance, if you are miking a sound source with one mic up close and the other a bit back in the room, so you can pick up some of the ambience, there is a chance that the mics might be out-of-phase with each other. See Drawing A:
As you can see, one mic is seeing the wave at a peak and the other at a trough, these mics would be 180 degrees out of phase to each other. To fix this you'd simply have to move one of the mics up or back until you heard that the signal was in phase.
Checking For Polarity
Finding out if your stereo signal is in good shape is an easy matter. A signal out of phase will have an absence of low end, sound very thin or even sound like it's coming from around the side of your head.The best way to troubleshoot this is to put the console output into mono by either pushing the mono button or simply panning the two channels up the center. Bring the volume of the two mics up at equal levels and then flip one or other of the mics out of phase using the phase button on the console. You should hear a marked change in the sound (for the worse) as you flip the polarity. If your home system does not have it you can wire a cable out of phase and put it somewhere in line with one of the mics. Although a bit cumbersome it is the same thing as pushing a phase button. In reality, the mics can be at any degree of "out-of-phaseness".
To wire a balanced connector out of phase, you simply swap pins two and three (XLR) or the tip and the ring (TRS) at one end of the cable. If you are looking for a phase button on a console or on a piece of outboard gear, it is usually represented by the following symbol:
The Three to One Rule
To place two microphones in a good phase relationship you can follow what is known as the Three-to-One rule. This rule states that for every unit of distance away from the sound source, your mics should be at least three units apart. For instance, if your mics are six inches away from the source then they should be eighteen inches apart. If they're 1 foot from the source they should be three feet apart. This will keep you in good shape when close miking instruments in stereo.
Hot Tip: A polarity switch will just correct signals that are 180 degrees out of phase. To correct signals at other degrees out-of-phase to each other, Little Labs makes an excellent tool called the IBP. (6.5.1997)
ORTF and X-Y
Last feature we talked about the 3-to-1 rule. This week we'll explore ORTF, spaced omni's and the x-y techniques of mic placement. A major consideration when miking in stereo is phase coherence. This means capturing the sound wave in the same part of the cycle in both microphones. There are specific miking techniques that will help you with this, one being the 3-to-1 technique. Another is called ORTF. This is an acronym for a French phrase that escapes me now, but the technique is this. Place the mics 17cm apart and angled at 110 degrees. If you do this with your fingers you'll see that it's supposed to simulate your head and how our ears are situated. Not a bad scheme to steal from mother nature! There are manufactured attachments that can sit right on a mic stand that will let you attach mics exactly in this configuration, or you could do it yourself. This technique works best with non-omni patterned mics. Omnis present their own specific problems that must be dealt with differently. Also, ORTF is best suited for small capsule mics. Large capsule condenser's off axis response is poor because of the capsule geometry. Because of this, if you use them in ORTF the undesirable off axis is pointing right at the center of what you're recording. Also, remember that when using ORTF, the more you spread the mics, the less focused your stereo image becomes. Turning the mics out exposes more of the sound source to the off axis side of the mic which shrinks and weakens your stereo image. Not spreading them as widely puts the source more on axis to both mics.
Omni patterned and large condenser mics work best when placed in spaced pairs. How far apart you space the pairs depends on what you're recording. Omni overheads on a drum kit, for instance, could be 3 to 4 feet apart. A large choir might take a 6 to 10 foot spacing. The best thing to do is to experiment a bit and listen to what you're getting.
Our last pattern this week is called x-y. This is simulating the x-y axes on a graph. The capsules of the mics are placed in very close proximity and pointed at or around a 90 degree angle (also called a coincident pair.) This placement eliminates phase problems because the wave hits both mikes at the same time. This placement doesn't work very well with omni mics: Although it's true that omnis become more directional above 1k, think of the omni pattern as two huge beach balls with the capsule of the mics at the center. If you put the two balls together it just makes one big ball and you have. Using the ideas and techniques in this feature can help you capture the best of what goes on in any recording situation. (13.5.1997)
Assignment: Cut 14 songs for a CD. This includes recording bass and drums and then overdubbing sax afterwards. All this had to be accomplished over a span of one and a half days.
We had the studio locked out from 6pm on Monday until 10pm the following evening. So needless to say time was tight and we had to work fast. We worked at Mad Hatter in Los Angeles. I can't say enough about how great the studio was. Great equipment, staff and facilities. The console was a beautiful Neve 8078 with GML automation. They treated us like kings from beginning to end. Mark the studio manager went out of his way to accommodate us and Darren my assistant was top notch. We also got a killer rate as there seems to be a price war going on in LA.
I had some special problems to deal with in pre-production for this project. The basic layout of the group was to be piano, bass and drums. The problem was that the piano player had been involved in a car accident and had injured his hands. He couldn't play for more than an hour at a time. So he recorded his performances on a midi piano into a sequencer. Then we recorded the performances onto 2-inch analog using a Yamaha Disklavier piano. Along with this I put down two different kinds of click so that the other players would have a choice. All this was done prior to our tracking date. We brought 5 reels of 2-inch along with us to the studio.
What Mics to Use?
Now onto the microphone choices for the session. The bass was taken direct using a Neve 1073 mic preamp, then to an LA-2A compressor and then straight to tape. As for the drums, it was a 6-piece drum kit with two snares, one was a piccolo. I used a D-112 on the kick, both snares got SM-57s, toms I used 414s, hi-hat a Shoeps and the overheads were two C-12s in a cardioid pattern, placed as a spaced pair. I took all the mics through the board except the overheads I used a couple of the outboard1073s that were available. Later for the sax I used a Neumman U-67 through a 1073 straight to tape. This combination of mics and mic preamps produced some of the best tracks that I've ever cut.
Overview
So to re-cap the miking scenario. I close mic'd all the drums except for the overheads. The toms and snares were miked at an angle about 2 inches off the surface of the drum. The kick mic was about six inches back from the beater head on the inside of the drum. The overheads were spaced about 4 feet apart and were about 2-3 feet off the tops of the cymbals. The hi-hat was angled and was pointed at the drummer from the outside. The sax mic's position varied as to the horn used. Soprano was between the bell and the lower third of the horn about a foot back. Tenor and alto was pointed back a foot and just above the bell but not facing directly into it. This is because the sound of the sax doesn't really come from the bell but from the keys as well. So it's kind of a general coverage scenario.
Keep your eyes here for more miking tips and a week from now a review of three Equitek mics. (20.5.1997)
So many instruments, so many mics and so many possible ways to set up a mic. This is indeed the truth but it need not overwhelm you. Using some simple rules like 3-to-1 and x/y technique you can cover a majority of the instruments on the planet. No matter which technique you use, it's important to find an instrument's sweet spot. That is the area best suited for picking up the best possible sound. For instance, an acoustic guitar's sweet spot is NOT directly in front of the sound hole. That spot is where the instrument is most boomy and doesn't lend itself to great recording. In the next few features we are going to cover very specific techniques for specific instruments, such as piano and bass.
Decisions, Decisions
Right out of the starting gate you should ask yourself if you're going to want to record the instrument in mono or stereo. Some instruments lend themselves to this and some don't. Things you'll possibly want to record in stereo are: acoustic piano, acoustic guitar (works great in mono too), some percussion (congas, bongos, misc. toys), background vocals (either by miking a large ensemble in stereo or by panning of individual mono passes), and drum kits (utilizing overhead mics and panning of individual drums). Things you won't want in stereo are: lead vocals, solo horns and woodwinds, bass guitar and individual percussion (shaker, tambourine etc.). If mono is your choice, then mic placement is a simple matter of finding the best spot and distance to pick up the instrument. Below is a list of instruments with general guidelines for miking them.
Mono Instrument Miking Technique
Acoustic guitar (mono) - Place the mic between the sound hole and the bottom of the neck, four to six inches in front of the instrument.
Trumpet - Place the mic four to six feet from the bell in front of the horn. This works well with multiple trumpets. It allows the players themselves to get a blend and play as an ensemble.
Saxophone - The sound of the sax does not come solely from the bell but from the keys and the bell. For tenor and alto place the mic four to six inches above the bell pointing at the top of the upper ring of the bell and keys (about a 40 degree angle). For soprano sax the mic should be at a slight angle and pointing at a combination of the bell and the keys.
Percussion - Tambourine should be miked four to six feet back depending on the sound of the room. What you're trying to go for is an ambient sound that gives you some space. Individual percussion like shakers and triangles can be miked a few feet back from the player.
Speakers - I've found that speakers have a sweet spot up close and that is where the dust cover meets the cone. See Fig. 1. If you're going for a more open and ambient sound, move the mic back four to eight feet depending on your needs. In this case the mic can be pointed in the general direction of the speaker and the above guideline does not apply.
(3.6.1997)
I was recently in Los Angeles working on an ongoing jazz project at Mad Hatter studios. The goal was to overdub piano on 12 songs and cut two new tunes; one live with upright bass and one solo piano. We used one of the two 9-foot grand pianos available in the A room, one is a Bosendorfer and the other is a Hamburg Steinway. After playing and listening to both, we chose the Steinway. I decided to use two AKG C-12 microphones for the recording and ran them through two outboard Class A Neve 1073 mic preamps. We ran some recording tests using various miking position and pattern choices until the artist had exactly the sound he was looking for.
Nuts and Bolts of Recording the Piano
As we talked about last week, acoustic piano lends itself well to stereo recording. There are a number of miking techniques you can use, depending on the sonic characteristics you're trying to achieve. If you're in an acoustically poor room, the piano is best mic'd up close so you don't have to fight with bad ambience. If the room is a good one you can move the mics back and get more of an open sound. Just a foot either way can change the tone a lot so be sure to experiment with placement and don't settle. Here are three basic techniques, two up-close and two pulled back.
Figures one and two show two techniques, one using two mics and one using three. Three mics would be used if you want more extension in the low-end. The microphones should be equidistant from the strings at about six to eight inches. Always check for the phase relationship by putting the console in mono and flipping the phase button. If you hear an absence of low end when you flip the button then you have your mics too close to each other. Refer to the feature on mic placement for some pointers on phase.
Figure three illustrates the technique I used for this session. The lid to the piano was opened to the long stick. The mics are about heart-high if you're standing next to the piano and just inside the outer lip of the lower frame. The on-axis part of the mic is pointing towards the strings at a 45 degree angle. With this scenario you can move the mics back or closer to get more ambience. This is very subjective and will vary depending on the piano, player, type of music, and the room. You'll notice I used the mics in spaced pairs rather than in an x-y configuration. This is because the x-y technique works best with smaller capsule microphones. Because of the capsule geometry in larger diaphragm mics, the off axis response can be boomy in the cardioid pattern. If you use x-y, you're exposing this off axis side of the mic to the center of the instrument. Spaced pairs is a better way to go with large diaphragm mics in cardioid pattern.
Picking a Pattern
Once we decided on the mic position we experimented with switching the patterns on the mic. We went from full omni to cardioid, passing super and hyper cardioid along the way. We recorded a bit of each and then listened back. We decided that a wide cardioid was the best sound; wide cardioid has a broader pattern and lets more sound in from the rear than regular cardioid. As far as EQ, I added 2dB at 12K to get some 'air' on tape. We were recording to analog two inch tape and I use a bit more EQ in this situation than I do with digital. The reason is because if you add EQ later, during the mix, you also boost tape hiss. (10.6.1997)
Recording electric bass is probably one of the easier tasks you'll undertake as an engineer; however, it gets a bit trickier to record when the bass is acoustic and playing live with another instrument. The objective for this session was to record an upright bass and piano together on a jazz ballad. Close proximity of the players was more important than isolation in this case so I opted to have the players in the same room. We built a nice portable 'room' around the bass player, (bassist, Paul Morin of Los Angeles), using some gobos. A gobo (short for go-between) is a portable wall on wheels that is about seven feet tall and six feet wide. There is sometimes a window at the top so players can see each other. In addition we put a carpet on the floor underneath the bassist to help tame reflections. See figure 1 to see the placement of the players in the room.
What Mics to Use?
The mics I used for the bass were two Neumann U-67 microphones (large diaphragm mics are my preference for upright). One microphone was about knee high pointing up at the bridge and the other about heart-high pointing at the strings, both mics were about 18 inches back from the instrument. We routed the mics through the board and I added a couple of dB at 56Hz on the lower mic. I also put the lower mic through an LA-2A compressor to tape. There was some leakage of the piano onto the bass mics but not enough to be a problem. The overall effect was like you were in the room listening to the players; very nice and intimate. The upright had a pick-up on it but in my experience these never sound as good as having it miked live. On the third try the players locked and rendered a beautiful take of the song. It was a pleasure working with such pro's with nice instruments.
Next week I'll be back from Germany and I'll lay out some live sound tips from the Bergerfest. (17.6.1997)
Last week we got into miking techiques and choice when recording an upright bass. This week I'm taking off on a bit of a tangent but it's related as far as mic placement and getting the most out of the situation you're in. My approach to live sound incorporates a lot of the things I've learned in the studio and through watching how others work, namely Robert Scovill and a few other colleagues where I teach. From watching them and asking questions, I've been able to get a lot of cool info that I incorporate when I do the occasional live sound gig. This last week I was at the Burgerfest in Regensburg Germany. There were 16 stages set up around town ranging from the small stage set up for dance and theatre to the very large setup for bigger bands. I was traveling with a 20 piece band that included dancers, singers and musicians. We were exposed to the very inadequate to the more than adequate stages in this large venue. I'm going to use this week to give you a quick overview on live sound and the theories I've used to make it work especially when you have limited resources.
Problem: You have a rhythm section including drums, bass, two guitars, two singers up front, four trumpets and a sax. You only have a ten channel mixer and 9 mics.
Solution: Punt. This was a bit scary. The venue was a large, open outdoor plaza with a nice size stage. But the sound system was woefully inadequate as was the mic selection. This was to be the worst of scenarios for these four gigs we were to play. I had to cover all the instruments and singers with the nine mics. In addition there was no snake, so I had to mix from the stage. YIKES! I basically just laughed and made lemonade. You've got to accept the fact that it's going to sound bad no matter what, but you can still make the best out of the situation with a careful setup and plan.
First off you've got to have someone in the audience whose ears you trust. For me that was my chum Steve Olea. In addition to helping me set up he was to be the point man who was to tell me what was going on 'out there.' My plan was VERY basic. Drums got a kick and an overhead mic. The drum kit had a front head on the kick which due to a quick setup I had no time to alter. If I learned one thing this gig it was, ALWAYS take off that front head. Even if you have to duct tape the drummer to stop his protests. In the studio, when the drummer has insisted, I've miked a kick drum with the front head on, never liking the outcome. I can surely say that I didn't like the outcome live either, too much leakage and no low end or beater definition. We ended up dumping it after the first song, leaving the drum kit way undermiked. But success is learned from a pile of mistakes and we all make them. Next I gave the trumpets two mikes along with a vocal mic for the left side of the stage. In addition the other side of the stage got two mics, one for vocals and the other for sax. Lastly there were two wireless mics that we used for the front vocalists. We brought our own with battery powered transmitters and mics, they worked flawlessly and I was impressed with the level I was getting out of them. I don't recall the brand but if you're interested send me some email and I'll find out for you.
After no sound check I just brought up faders nominally and used the first song to set up my mix. EQ was guess work as was initial fader levels. I had no compression and no reverb. The compression is what killed me. The vocals were so dynamic that they ate up all my headroom and then some. My kingdom for a DBX 160 and a subgroup insert! Due to the fast pacing and number of cues in the show I had to remain at the mixing position, never getting to go out and hear for myself what was going on. So I relied heavily on my point man. Through a number of hand signals he related to me overall level adjustments. For real trouble spots he came up to the stage and related what had to be changed. As the crowd got thicker (1500+) he had to remain out in the house. We got through the show and got the encore chant (zu ga-bay, zu ga-bay) so I guess it was good enough for an encore at least.
Recap
The lesson I learned here was that no matter how good you think you are, you're only as good as the equipment you use. No amount of skill can make up for bad or inadequate gear. Humility is a good thing.
Next week I introduce a new studio toy I just got and back to some more miking scenarios. (24.6.1997)
What's Important?
One of the most challenging things to record is the human voice. To get the right performance, you not only have to be a competent engineer, but sometimes a cheerleader and psychologist. First let's lay out what it takes to get a good vocal sound. I stress signal chain time and time again and here I'll say it again: The room, mic, cables, pre-amp, compressor and recorder will determine the sound you get. My recommendation is to use the best you can afford in all categories. If you don't have the best in one department, borrow or rent something if you have an important session. My favorite choices for female vocal is an AKG C12, for male vocals it's a Telefunken 251. Both of these are tube mics and sound great, but they're also expensive. If you have a few to choose from, don't be afraid to try them all. Time spent up front experimenting is never wasted. The limiter/compressor you use is just as important, some styles of music call for a compressor with a big footprint. This means that you can hear it working. Other styles, like Jazz, call for a more transparent sound. Train your ear to hear what compression sounds like in a track. I would bet the farm that there is compression on 99% of the vocal tracks you've ever heard. The bottom line: Always use the best gear you can.
The Surroundings
The recording environment is just as important as the signal chain. A recording space that's too live will cause ugly reflections back to the mic. In this case, it's necessary to deaden the room. This could involve anything up to and including nailing packing blankets to the wall and stuffing foam behind them. Remember you're not only recording the vocalist but the room that they're in. The pros use gobos to build a 'room' around the vocalist. I was able to use gobos to great effect in isolating an acoustic piano and bass player at a recent session. In addition For vocals, it's a good idea to lay down a rug to keep from picking up tapping feet and deaden the floor reflection. Another thing to keep in mind is the angle and reflection off of the music stand. You don't want the vocal reflecting off the stand into the mic, this can cause phase problems. An easy solution is to put some kind of refractive material on the stand such as a piece of thick carpeting or a towel. Also be sure to angle the stand down a bit so the reflection is going away from the mic.
Where Does the Mic Go?
Positioning the mic is crucial in getting a clean sound without any plosives. A pop screen will be needed in addition to precise positioning. Plosives are the Ps and Ts that ruffle the diaphragm of the mic, causing unwanted low end information to get onto your recording. Position the mic so the diaphragm is just below the singers nose and pointing down towards the mouth at about six inches away. Then put the pop screen (a ring with a nylon material stretched over it) between the singers mouth and the mic. This should be sufficient to do the job. Some repositioning may be necessary if you're still having problems. I've also had problems with rattling jewelry and popping gum. (I'm starting to sound like a grade school teacher!) If this gets on tape it will be impossible to extract later.
Psychological Aspects
Last and most important is making the singer comfortable. A great headphone mix helps. I've also brought candles into the studio and dimmed the lights for a good vibe. I once worked with a singer who was very good but had no confidence at all in her ability. If this happens make a concerted effort to use no negative language. When they say THAT SUCKED! You say, 'that pass was good, now lets go for a bit more power (or whatever you're needing for the track)' I don't use the word 'no' or 'don't' or 'never,' only positive language and encouragement. I've used this technique a lot and have gotten great results. People will respond to praise and positivity and by the end of the session will thank you for helping them sing better. (1.7.1997)
Recording live brass is a lot of fun and it's not that hard to do. There's nothing like a great brass section playing a great chart to really kick a track in the butt and make it sing. Even though synths and samplers are able to copy a lot of horn sounds very well, there is a 'freeze-dried' sound to sampled brass that, frankly, sounds boring.
The Basics
By following a few simple guidelines, you can get a great horn sound.
First, keep in mind that horns play best as a section. There are numerous
cues and signals that a section gets from one another that makes them play
as a team. Taking one horn and multi-tracking it over and over will not
give you this 'team' sound. Your best bet is to find a group of
players from a band, or better yet, session players who have played together
time and time again. Remember, this is an ensemble, complete isolation is
impossible. Putting the players in separate rooms defeats your purpose.
A certain amount of leakage is inevitable and not necessarily a bad thing.
However, you can give yourself more flexibility when mixing by placing the
players properly in the room. Figure 1 shows a layout example for a seven-piece
horn section. The placement of the players and use of a cardioid
pattern mic will limit the leakage into opposing mics. I like to use
one mic for the trumpets. This puts the blend responsibilities on the players,
where it should lie. Also, the less mics you have in the room the less phase problems you'll have.
Expect a lot of trumpet leakage into the other mics, simply because they are the loudest of all the instruments. By close miking the trombones and saxes you will get more level onto tape and help with the trumpet leakage. Also, notice in Fig. 1 that the mics used for the trombones and saxes are off-axis to one another. This also helps with the leakage.
The mic for the trombones and saxes can be six inches from the bell. If you were miking these instruments solo, you would have the luxury of backing the mics up a bit. On saxes especially backing up the mics is desirable because the sound of a sax does not come solely from the bell, but from the keys as well. So if you back it up a bit you'll get a better sound. However, in ensemble the closer scenario is better.
Track Layout for Flexibility and Big Sound
By taking the three groups of horns to three tracks on your multi-track, you'll give yourself the best possible opportunity to blend the horns during mixdown. If you're looking for a bigger sound, doubling is great way to make your horn section sound huge. To save tracks on the second pass of a double you might combine the saxes and trombones together and only use two tracks, one for trumpets and one for sax and trombone. This way you have the best of both worlds, individual tracks on pass one and the big sound of a double. (8.7.1997)
Recording drums is probably the most challenging situation you will ever come across in the studio. The microphones you use and how you place them is important, but some initial preparation will help you get great drum sounds and really lay a nice foundation for your track. In major recording centers like Los Angeles and Nashville, having a tuned kit with new heads is the standard operating procedure for all the first call studio drummers. They have full time drum techs who cart their drums around, change the heads and tune them before each session. However, if you're working in the other 99% of the country, you as an engineer might have to take responsibility for making some of those things happen. When I'm doing the pre-production meeting for a session (which can be as simple as a phone call), I always tell the band and drummer that if you want this record to sound great, put new strings on the guitars and new heads on the drums (tuning an acoustic piano is also a must). No amount of EQ or signal processing can resurrect a cardboard sounding drum kit after it's recorded. You must have a good sounding kit up front and it must be tuned. I found a great tool for helping me tune drums with the Drum Dial. It's featured under product of the month, it's worth checking out.
The Environment
Something you need to assess and be aware of is the room you're recording in. Not only are you recording the drums but you're recording the space that they're contained in. A room that has acoustical problems such as standing waves and ugly uneven reflections can ruin the best sounding kit. If you are stuck recording in a poor room you may have to put up some packing blankets or use gobos to help you tame down the room.
Now that we've established the importance of having a good sounding kit and room, the next step is to get it on tape (or hard drive). Making a drum kit sound like one organic unit is always my objective. For starters, stand in the room as the drummer plays and actually hear what the kit sounds like in that space. Then try to emulate that as much as possible. Because of the number of mics used in recording a kit, you could run into the problem of it sounding too much like a collection of separate drums. You want it to sound more like a whole instrument rather than a group of individuals. (15.7.1997)
Kick drum:
You need a mic that will handle high SPL (Sound Pressure Level) and also cover the low end as far as frequency response goes. Some choices are:
Snare drum:
I've tried a number of others but still keep coming back to this simple, inexpensive mic. I love it. Another option is to use a second mic on the underside of the snare drum. This can be another 57 or perhaps another dynamic mic like the Beta 57. If you have a condenser that can take the SPL then by all means try it. The idea of this mic is to accentuate the sound of the snares on the underside of the drum. Mixed with the top mic it can give you the snap that you need if you aren't getting it from the top of the drum.
Hi-Hat:
Toms:
Overheads and room mics:
Basically any matched pair of condensers will work here if you're stuck. For the most part you'll want a cardioid pattern for the overheads and you can experiment with the room mics.
These mic choices are just guidelines. You may have your own favorites or want to try others. The important thing is to get the killer sound that you need to make your track a standout. Next feature, we will be covering microphone placement for all the different drums. (22.7.1997)
Last feature we picked a number of mics that would be good for recording a drum kit. Now we'll discuss specific microphone placement strategies.
Kick drum:
For me, the best scenario is to have the mic inside the kick drum. You'll never get great beater definition and isolation if the mic is outside the front head. I've heard of guys miking the outside of the front head and then miking the beater side. I've tried this and it was a nightmare of leakage and didn't work for me. I like to put the mic inside the drum. This can be accomplished by taking off the front head or if there's a hole in the head, putting the mic through and positioning it inside. If the head is all the way off then it's a good idea to build a little isolation 'house' around the outside of the front of the kick. A chair, some duct tape and a packing blanket or two will work nicely for this. This will help isolate the drum and your mic. In addition you may need to put a blanket or a pillow inside the drum to deaden the inside a bit. A kick that's too live will give you little definition and can be ugly. DW Drums (Drum Workshop) makes a nice hourglass shaped pillow that is cheap and works great.
I place the mic a little more than half way into the drum and point it just to one side of the beater. I've seen others put it more off axis to the beater head depending on what the drum sounded like. You'll have to experiment and see what's right for your particular situation.
I recently talked Robert Scovill about how he miked Neal Peart's kicks for the most recent RUSH tour. He came up with a home rigged mic assembly for the inside of a kick that has the front head on it (no hole). He criss-crossed some cables that he rigged on the inside of the kick and fixed a mic clip to it at the center. He used turnbuckles to get the mic clip placed precisely where he wanted it. Once he fixed the mic inside he closed up the outer head. The cable came right out of the drum and could be sent to the snake easily.
Here are some scenarios for placing mics on a drum kit:
Snare drum:
Snare is miked as in Fig. 1. About 2-3 inches off the head and pointed in from the side. This keeps the mic out of the drummers way and vice versa.
Toms:
Tom miking is very much like the snare in Fig 1. Sometimes if I'm not getting enough low end from my low tom I'll put a condenser or a D-112 underneath the bottom head. This is then mixed in with the top mic, and after checking for phase, is sent to a separate track on the tape machine. If you're feeling brave or have limited track resources, you could mix this with the top mic feed to one track.
Hi-Hat:
There are a number of different techniques for hi-hat miking. The desire is to keep the other drums out of the hat mic as much as possible. I've seen it pointed away from the drummer and down at the outer edge of the hat from the top. You have to watch that the mic isn't pointed at the bell because it tends to sound very pingy and thin. Also, don't get too close to the closing edge because a puff of air comes out every time the hats close and that can ruffle your diaphragm and make for nasties on tape.
Overheads and Room mics:
Overheads can be placed in an x-y configuration or in a spaced pair. (see the feature on mic placement) If you use omni patterned mics then the spaced pair is the way to go. Large diaphragm condensers tend to work better in spaced pairs also. Small diaphragm mics work great in either scenario. In general I put the mics about 6 to 7 feet from the floor and if spacing them, try to capture a balanced sound from all cymbals and toms.
Room mics can be placed equidistant from the front of the kit and back. How far back and how wide you place them will determine how big your room mics sound. Remember that for every foot you add one millisecond of time delay from the source. So if your room mics are back 10 feet you're mics will have a delay of about 10 milliseconds. The best rule is to experiment and see what you get and if it pleases you and compliments the music then go for it. I always print room mics separately.
Once again these are just guidelines. You should make yourself aware of as many techniques as possible and try them for yourself. (29.7.1997)
Track Sheet Layout
How you lay out your track sheet depends greatly on how many tracks you can afford to dedicate to your kit. The best scenario is total isolation of all drums. I like to dedicate a track to each tom, but you can sum these to stereo if you're stuck for tracks. The reason for all the isolation is to be able to treat each individual drum with, EQ, panning and reverb. Once you sum drums to stereo you'll not have the flexibility to do this (EQ for the group of toms can be done in stereo however). (see August '97 Question of the Month).
For our purposes let's say you have 24 tracks available. Below is an often used layout for drums within this framework.
Notice the extra info as far as panning and which side of the kit the drums are from. Very important info for the next engineer down the line. You might also include what mic you used.
EQ Guidelines
As far as EQ goes, I've said in the past that EQ is the LAST thing you should do to make something sound better. Mic placement and choice is your first refuge when things are not sounding good. Also, keep in mind that new heads and tuning goes a long way in making a drum kit sound great. (click here for a feature on advanced drum tuning) In light of that here's some general EQ I use when tracking.
Kick drum:
Snare drum:
Hi-Hat:
Toms:
Overheads:
This is all very subjective and depends on the kit you're recording. So it's NOT gospel, just meant as a guideline. By the way, I never gate to tape, only from tape, and I always EQ to tape, especially if analog. Everyone has their own particular style of recording. This is mine. You will be a better rounded engineer by getting a lot of different perspectives on recording and taking what you like from that. This way you'll develop you're own style. (5.8.1997)
Direct or Miked?
There are two ways of recording electric bass: Either by taking a direct feed out of the instrument and putting it through a direct box, or miking the speaker of a bass amp. In the studio, it would be safe to say that the majority of bass recording is done direct. Doing it that way solves a lot of leakage problems and makes it easy to get a great sound. This is not to say you can't mic a cabinet as an option. In fact, it's a good approach to isolate the bass cabinet and mic it during the session or to reamp it afterwards. This way you could have different tracks for the direct and miked feeds and then mix them later. It's actually very easy to split the signal in this way, because in addition to the balanced output, a direct box has a thru. This way you can take the unaltered signal from the bass and plug it right into an amp. This is invaluable for live situations where you'd want to take the direct signal through the desk for the front of house and monitors and also have the bass plugged into the player's bass cabinet on-stage.
Why Do You Need A Direct Box?
When recording direct, a direct box is needed because the output of the bass is high impedance, and a console likes to see a low impedance input. In addition, the bass is unbalanced, and most consoles, even down to a Mackie, will take a balanced input. A direct box is kind of a translator that takes an unbalanced high impedance signal at the input and produces a balanced low impedance signal at the output. Direct boxes come in passive and active varieties. An active DI needs power to run and a passive one does not. Power is supplied by either a battery, or by phantom power from the console. Either style works fine, so it boils down to a matter of personal taste for the type of music you're recording. Personally I like to use my Calrec mic preamp as a DI at the front end. A lot of standalone mic pre-amps will have a 1/4" input on the front so you can use it as a DI. I get a lot of questions about compression and bass and I'd say it's safe to say that it is common to compress the bass when recording. This limits the dynamic range and keeps the bass up in the mix without eating up all your headroom.
Using these guidelines will help you record a nice clean signal and give you some flexibility later on when you mix. (12.8.1997)
Last week we covered the recording of electric bass, this week we get into some advanced drum tuning techniques.
Tuning is the thing
Some of you use a house drum kit when you record. Whether it be your own kit or one you have access to, accurate tuning can make your recording experience a pleasant one. In an earlier feature we talked a bit about the importance of tuning drums. Now we get down to the meat and potatoes of tuning. I'm sure you've all heard the joke about the drummer who says 'You mean you can tune these things?' It's the last thing a drummer learns if at all and it's THE most important thing in recording. If you have garbage as your source, even the best signal path won't help you.
I have to give all of the credit for the following information to the DW Drum Company. A student of mine compiled their data for a recording business presentation. I've just paraphrased it for you here.
Theory and Execution
Each shell of a drum kit has a resonant frequency. The frequency can be found by removing all the hardware, suspending the drum and tapping it to find the tone. This can then be matched to a tuning fork etc. as a tuning source. Once you find the resonant tone you use this to tune the drum heads.
The important thing is that no two drums of different sizes overlap each other's timbral frequency range. Ultimately you want a set that's matched in tone. The intervals far enough apart so the drums complement each other without the sympathetic vibrations causing problems. Bigger drums such as the kick and low tom should be a fifth apart where as you get smaller and smaller it can be a fourth apart. DW matches their drums in this way and sells the sets with complimentary midrange timbres and traditional intervallic relationships. However you can find the pitch of any drum in the way I described above.
Once the pitch is found you can then match the upper and lower heads to this pitch. Then using a precision tuning device such as the Drum Dial you pitch the upper head up and the lower head down a bit from the shell's pitch. This makes the drum heads ring with a sympathetic tone and have a desirable sustain and timbre. When you tune a whole kit in this fashion and memorize the settings on the drum dial, it's just a matter of keeping the kit maintained properly. It's science when you use the proper tools. I can't stress enough the importance of getting into recording on this ground level. You can't expect merely a knowledge of consoles and microphones to get you through a session. It's important to know a lot about guitars, drums, humans etc. to get you great results. Keep your eyes here for more info along these lines. (19.8.1997)
The Problem
A recording studio can have miles of cable running from here to there and back again. When making cable runs of any length it's important to be able to reject any noise that may jump onto the line from a number of sources. Radio Frequency (RF), noise from dimmers or fluorescent lighting, CB radio transmissions, AM/FM radio transmissions and more can end up hitchhiking along with your signal. Think about it, when you lay out a length of cable you are essentially making an antenna. When you lay out thousands of yards of antennas it can be a nightmare.
The Solution
The best way to remedy this is to used balanced connections throughout your studio. The difference between balanced and unbalanced cable is an extra conductor in the wire. An unbalanced connection runs two conductors, a hot (+) and a ground. A balanced connection runs three conductors, a hot (+), a cold (-), and a ground. What makes the difference is not in the cable but in what happens at either end, before and after the signal travels down the cable. Any cable can be an antenna and a noise collector.
First lets look at balanced connectors. You can see that they come in two common forms, one is an XLR or cannon plug and the other is a TRS 1/4" connector. Don't confuse this balanced connection with the balanced connector that's used on some consoles. On a number of Mackie consoles for instance, they use a TRS to run an insert in and out of the board. This is not balanced but using the three connections as in, out and ground. One connector does the job of two and it's not balanced.
What makes a balanced connection work, is some electronic trickery that makes the noise on the line phase cancel itself out of existence. (Remember our feature on Phase?) Here's how it happens. A balanced connection first runs through a differential amplifier which splits the hot signal into two and flips one half 180 degrees out of phase. This travels along the cable as plus and minus along with the ground on three separate conductors (on an XLR, pin 2 is hot, pin 3 is cold and pin 1 is ground). Along the way, the usual noise is encountered and picked up by the line. At the other end of the connection, the minus is flipped back into phase and you end up with a plus and a ground again, just as it was when you started. The difference is, that now the noise is out of phase with itself and cancels completely. (26.8.1997)
Last week we talked about console dynamics. As long as we're on the subject we're going to further explore the basic set-up of gates and compressors.
The Starting Line
Just like you do certain things to set up your car when you start it (seatbelt on, car in park or neutral if it's a stick etc.), there is a basic starting point that you can use when setting up compressors and gates. This makes it much easier to get the device to do what you want it to do right off the bat. If your device has been used in a previous session and is already setup for something different than the instrument you're going to use it on, it can be a challenge to get it going. Not that I'm not one for challenges, but if you can start out the device fresh your job will be easier. The idea is to use the following setups as a starting point and then tweak your signal until you get exactly what you want.
Compressors
The routine for setting up a compressor is as follows:
I'm purposefully using a very simple compressor such as the DBX-160X as a template here. Other compressors may have more features, but if you can start out with this one and can master the basic parameters, then you can easily jump to something more complex using the same principles. Before we run through what each parameter does, let's explore compressors for a second. Compressors work by leaving all the audio below the threshold untouched and compressing all audio above the thresh