In the last post I talked about how surprised I was to learn that my mic choices had been largely dictated by my habit of close miking everything. Many instruments and stage setups do not require close miking, and some even sound worse with it. Think of all of the opportunities for phase cancellations that you introduce by using so may microphones in close proximity! How about eliminating some of those microphones by single miking multiple sources using a condenser microphone?
You’re afraid to try it, right? I’m afraid to try it. How will we get enough volume before feedback?? This solution doesn’t work for every situation, but Philip Graham reminds us to change our expectations in his article, Single-Miking Bluegrass-Style.
Get Close to the Mic
[quote name=”Philip Graham”]The first point to understand is that the distance from your instrument or voice to the mic is the first gain stage in your chain. It’s a negative one – the sound level is always quieter at the mic than at the instrument, and it drops with the square of the distance. So it’s twice as quiet from one foot as from six inches away, and twice again as quiet at two feet. In order to get the same signal level in the PA, the preamp has to add that much gain back. More importantly, assuming the level of sound on the stage from the PA (mains and monitors) is the same, the microphone has to be able to deliver that much extra gain without feedback. The farther you are from the mic, the harder it will be to get the same volume from the mains without running into feedback. So the first best technique is to really work on being able to play close to each other and to the mic. Many people place the mic too high, getting it needlessly far from instruments like the guitar and banjo, especially if vocals aren’t a major part of the band’s sound. Picture lengths of string from each sound source to the mic, and try to balance them all and keep them all as short as possible. One foot makes a big difference.[/quote]
Louder Instruments to the Sides
[quote picture=”http://sounddesignlive.com/wp-content/uploads/2013/06/sound-design-live-philip-graham-head-thumbnail.jpg” name=”Philip Graham” align=”left”]To fight feedback you want the greatest contrast between the sensitivity directed towards your instruments and that directed towards anything coming from the PA. So keep your players to the front of the mic, ideally all within the 60 degree arc. Place your louder instruments to the sides and the quietest in the center. Keep the mic at least some distance behind the main speakers. And keep your monitor (you should only need one) a little distance behind the mic (from the band’s point of view) – don’t put the monitor right at the foot of the mic stand.[/quote]
I’ve only used this technique successfully in spaces with high ceilings and absorbent walls where the sound system is flown ten-plus feet above the stage. Watch out for low ceilings and reflective back walls. Philip suggests angling the mic’s peak sensitivity away from problematic surfaces.
I really like the single mic sound for duos singing and playing acoustic guitars. A more common setup is to close mic all four sources, but the mics are in such close proximity that I can almost always hear phase cancellations and bleed messing up my mix. Angle the performers to face each other, put a figure-eight polar pattern condenser microphone in between them, and you’ve got a sweet-sounding solution.