Question from an Audio Masterclass student: “I tried miking a clarinet by taping a mic onto the bell but when some of the holes are uncovered, the sound becomes softer. What to do?”
Leaving aside the question whether the King of Clarinet is Benny Goodman or Artie Shaw, it is a fact that clarinetists tend to move around a lot, particularly jazz clarinetists.
So whether for recording or live sound, the engineer has a problem where to put the microphone.
But there is one obvious answer – put the microphone where the sound comes out and fix it to the bell. This is very easy to do with miniature clip-on microphones, and indeed special clips are available for just this purpose.
But there is a problem. Although it might seem intuitively obvious that the sound comes out of the bell, in fact it comes out from the whole length of the instrument.
Stand next to the clarinetist and get him or her to play a few scales. You will clearly hear that the position of the main sound output changes according to which holes are covered.
And when all of the holes are covered to play the lowest note the instrument is capable of, then suddenly all of the sound comes out of the bell.
Clearly then a microphone taped to the bell will pick up very uneven levels.
There is no real 100% solution to this, but a partial solution is to have the microphone attached to the bell, but on a short boom and positioned outside of the bell. This way, the microphone will pick up a much more even sound that doesn't change in level from note to note.