Microphone Choice and Placement Secrets for Recording
Contributor: Bobby Owsinski
While you often see microphone techniques discussed for specific applications, another approach is to learn some general principles that you can apply to any situation. Before we can get into that though, we have to choose the proper mic first. Lynda.com's Bobby Owsinski, author of the site's online video series Audio Recording Techniques and the Audio Mixing Bootcamp leads the way.
Let's take a look at how that's done.
Choosing The Right Mic
While there may be a mic that works well for many applications, no single mic works great on everything. In fact, thanks to parameters like diaphragm type, polar pattern, and sensitivity, having a nice variety of mics can really make a difference in the final sounds that you're recording and how they blend together in the mix.
It's safe to say that most engineers rely on their experience when choosing microphones, but there's also some sound reasoning behind their preferences. Here are a few things that you might want to consider when selecting a microphone to record with.
Does the microphone complement the instrument that you're recording?
For instance, if you have an instrument that has a very edgy top end, choosing a mic that also has that quality may have those frequencies further emphasized when recorded. You might want to choose a mic that's a bit mellower, such as a ribbon. This is one of the reasons that a ribbon mic works so well on brass, for instance.
Will the mic be overloaded by the source?
Some mics just can't take an extended amount of sound pressure level without generating some sort of distortion. A ribbon mic or many condenser mics won't work on a snare drum with a heavy hitting drummer for just this reason. That's why the level of the source always has to be a consideration when choosing a mic.
Does the mic have the right polar pattern for the job?
The directional pickup of the mic needs to be considered before making a mic selection. For instance, if leakage is a consideration, then you may want to try a mic with a tighter directional pattern, like a hypercardioid. If the instrument you're miking radiates in multiple directions (like an accordion, dulcimer or bassoon), sometimes an omni pattern works wonders. Either way, don't overlook the polar pattern when choosing a mic.
Is the proximity effect an issue?
If you're going to be close-miking, will the low-end buildup from the proximity effect of a cardioid mic change the sound too much? If so, this also might be a good place to try an omni, or at least move the mic away from the source a little.
Now that we've covered some of the parameters that go into choosing a microphone, mic placement is the next area that can affect the sound you capture. Let's take a look.
Secrets Of Mic Placement
Quickly finding the optimum position for a mic is perhaps the single most useful talent an engineer can have. You should always trust your ears and begin by listening to how the instrument sounds, find the sweet spot, and begin your microphone placement there. If you don't like the resultant sound, then move the mic or swap it with another. EQ should be the last thing you touch.
Microphones can't effectively be placed by sight alone, which is a mistake that's all too easy to make. That's why it's important to actually listen to the instrument before you place the mic and find the place where the sound has the most balanced representation of the instrument, or the "sweet spot."
How To Find The Sweet Spot
Depending upon pickup pattern of the mic you'll be using, you'll have to approximate the way it captures audio when you're listening. Here are some tips on just how to do that.
- To correctly place an omni microphone, cover one ear and listen with the other. Move around the player or sound source until you find a spot where the frequencies from the instrument are the most balanced and place the mic there.
- To place a cardioid microphone, cover one ear and cup your hand behind the other ear and listen. Move around the player or sound source until you find a spot where the frequencies from the instrument are the most balanced.
- For a stereo pair, cup your hands behind both ears. Move around the player or sound source until you find a spot where the frequencies from the instrument are the most balanced.
The Sound At The Source
Contrary to what many might think, just having great recording equipment doesn't automatically guarantee that you'll capture great sounds. The problem is that you can't really quantify how much each variable in the recording process contributes to how a recording ultimately sounds, since each situation, even within the same project, is unique. That said, you can generally break it down to something like this:
- The player and the instrument contribute at least 50% to the overall sound (sometimes a little more, sometimes a little less – but always the greatest portion). Simply put, it's got to be in the fingers (or embouchure, or vocal chords, etc.) first.
- The room contributes about 20% to the overall sound. Even on close-miked instruments, the room is far more responsible for the ultimate sound than many engineers realize.
- The mic position contributes about 20% to the overall sound. Placement is really your acoustic EQ and is responsible for the instrument's blend in the track.
- The mic choice contributes about 10% to the overall sound. This is the last little bit that takes a good sound and makes it great.
If something doesn't sound right, there are a lot of things to change before you reach for the EQ. Try the following in this order:
- Change the source, if possible (the instrument you're miking)
- Change the mic placement
- Change the placement in the room
- Change the mic
- Change the mic preamplifier
- Change the amount of compression and/or limiting (from none to a lot)
- Change the room you're recording in
- Change the player
- Come back and try it another day
General Mic Placement Principles
Instead of looking at the mic placement used on specific instruments, here are a number of guidelines that work in almost any situation.
- One of the reasons for close-miking is to avoid leakage into other mics so that the engineer can have more flexibility in balancing the ensemble in the mix. If at all possible, give the mic some distance from the source in order to let the sound develop, and be captured, naturally.
- The best mic position cannot be predicted, it must be found. It's OK to start from a place that you know has worked in the past, but be prepared to experiment with the placement a bit since each recording situation is different. The song, arrangement, player, instrument, recording environment, and signal path all have a bearing on the final sound, and chances are that at least one of those parameters has changed since the last time you recorded.
- If the majority of the sound will come from the room, start getting sounds from those mics first, and then add any other mics that act as support.
- The 200 to 600Hz range is where the proximity effect often shows up and is why many engineers cut the EQ in this range. If a number of directional microphones are being used at the same time in a close-mic situation, they will all be subject to the proximity effect, and you should expect a buildup of this frequency range in the mix as a result. This is another good reason to use a variety of mics and different directional patterns, so that the proximity effect buildup is diminished.
- A huge sound is a larger than life sound, but that doesn't always come as a result of something being loud. One way to accomplish a larger than life sound is by recording a sound that is softer than the recording will most likely be played back. For instance, sometimes an electric guitar run through a 5 watt amp with an 8-inch speaker can sound bigger than a 100 watt Marshall stack.
The above guidelines can be used in just about any recording application and will help you deliver a sound that goes way beyond the normal cookie-cutter "this is where to put it" mic placement. Good recording!
ABOUT BOBBY OWSINSKI: He is the author of 16 books on recording, music and the music business as well as several outstanding, step-by-step video courses for Lynda.com, including Audio Recording Techniques, Audio Mastering Techniques, Mastering for iTunes and the Audio Mixing Bootcamp.
Learn more at: