Microphone Placement: Art Or Science?
Tips and techniques to help you capture the sound you’re hearing
The simple act of placing a microphone near an instrument to capture its sound is often shrouded in mystery. With so many options of where to place the mic, what mic type to use and how to optimise the setup, it can be quite daunting. Thankfully, there are a few basic principles which can be adhered to which should make recording good quality sound a bit more accessible. Let’s have a look at some of the basic theories around microphone placement.
Variables, variables and more variables
As with many musical practices, there is one basic, simple rule. If it sounds right, it is right. If you find you can nail the sound you want by hanging out of the kitchen window while your band strums away on the patio in the rain, then that is the right technique. Alternatively, if you get amazing results by placing 14 different microphones around a single snare drum, good for you. It’s part of the beauty of the recording process; there are no right or wrong answers. But let’s say you have a fairly simple task to do, like recording a guitar amp, and are finding the results you are getting to be quite bland. We can begin to remedy that by discussing some of the many variables around microphones, and mic placement.
An important one to start with. The polar patterns of your microphone will have a huge impact on the sound you record. Essentially, polar patterns are the direction at which the microphone looks for the sound source. It’s crucial to choose the right mic for the job here. If, for example, you’re recording a snare drum using a microphone with a 360 degree (omni-directional) polar pattern then you’re entering a world of pain.
Briefly, a cardioid pattern microphone picks up predominantly the sound in front of it. Its design ensures it can dampen, if not completely ignore, sound coming from any other direction than smack bang in front. This makes it ideal for recording vocals, guitars, amplifiers – anything where the sound is output directly in one direction. Super-cardioid and hyper-cardioid develop this principle even further by narrowing the field even more.
Omni-directional mics, on the other hand, pick up signals from all around. This type of mic is best suited to recording groups of singers, or for capturing specific room sounds which you may find desirable. Say you’re recording in a room with amazing natural acoustics; an omni-directional mic used in conjunction with a series of cardioid pattern mics can bring great ambiance to your recording.
The other major factor in choosing and placing a microphone is what you’re trying to capture. Again, there are no hard rules but certain setups will naturally sit better with specific applications. Let’s choose a few familiar examples and discuss some of the options.
Recording an acoustic guitar
Assuming the guitar in question is being recorded acoustically, as opposed it being an electro-acoustic with an in-built pickup, we can get some good results with just a single microphone. The cardioid pattern of an Aston Origin condenser mic, for example, pointing directly into the sound hole is a good place to start. From there you can begin experimenting with how close or far away you place the mic. The closer the mic is to the sound hole, the more bass frequencies the mic will pick up. You could also point it toward the bridge of the guitar for a slightly more mellow sound, although it can begin to lack definition at certain distances.
Recording an amplifier
As we all know, guitar amplifiers tend to sound better when they’re driven harder, so they’re able to produce more of those glorious power amp valve harmonics. That requires volume. With that in mind, it’s preferable to use dynamic microphones here. Rather than mic’ing from a distance and trying to capture the entire cabinet, you’ll have far more success choosing one of its individual speakers and experimenting with that. Locating the mic fairly close (a few inches) to the speaker’s cone, try moving it around. You’ll be surprised how much impact can be had by just moving the mic even a couple of inches. Pointed directly at the cone’s centre, you’ll get a fairly harsh sound with a super-quick attack. This tends to suits heavier styles of guitar, but may be too extreme for other styles.
For less aggressive styles, a good technique involves using a dynamic mic to capture the sound immediately from the speaker cone, with a second mic – usually a condenser – placed a few feet back to capture more of the room. Blended together at the mixing stage, these two sounds complement each other superbly, offering both warmth and clarity at the same time.
Recording a drum kit
Drums are easily one of the hardest instruments to mic correctly. For starters, and excuse us for stating the obvious, drums are loud. Not only that, the individual components of the drum kit share hardly any of the same frequencies. This brings about its own set of unique problems for recording, but they’re not insurmountable. It’s perhaps here that the mic’s polar pattern is most critical. Remember the super-cardioid mics we mentioned earlier. They come into their own for recording drums, where you want to capture the sound directly in front of the mic and nowhere else.
These are just a few examples of different methods for recording instruments. Microphone placement is perhaps best described as equal parts art and science. There are undeniably certain principles which must be adhered to. Choosing the right polar pattern for the job is crucial, as is the type of microphone. But there’s also huge opportunity to experiment with where you put the mic, and at which angle. Movement of even just a few inches can completely change the sound, so play around with the tools at your disposal.
It might not seem it, but good microphone placement is a hugely creative process. It’s also one which is rewarded by experimentation and an adventurous nature.
View a complete range of microphones over at the Dawsons website.