isolating mics for directionality?

[ZOWIE!]

I was thinking about building a sort of box or shield out of soundproofing foam tiles to put arround the back and sides of a mic to enhance its off-axis rejection.
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Any reason why this is not a good idea?

 

[Chibi Nappa]

Might be interesting. Just keep in mind that bass waves need very large and deep structures to be absorbed, so you'll probably reject sound unevenly across the audio specturm. You also might cause some strange standing wave patterns with sound bouncing around in the box there....

I'm not saying don't give it a shot. God knows stranger mic tecniques have been used with great sucess.

 

[fenix]

i've seen this done many many times in pics of PRO studios when using condensers on the toms.

I don't see why you couldn't do this.


ps...audix drum mics have some of the best specs for off axis rejection at 30db!!!

 

[mixsit]

I was tempted to try this with a pair figure-of-eight mics. I figured a solid back piece -box, half-sphere or tube perhaps, to stop the rear source sound, and be large enough for 2-3" of internal padding to control down to a few hundred hz. (just estimating..)
Fig-8's have very deep control at 90 degrees so it seems like a good start point.
As Chibi mentioned, the lows would might never be reduced much, but I wonder if it would be all that much worse than the effect of a typical gobo isolator in that respect.
I did a plexi-glass shield with 1" of foam inside for a snare/hat shield. It helps a little, but it's only partly covering the mic.


"ps...audix drum mics have some of the best specs for off axis rejection at 30db!!!"
Audix makes nice mics, but some of their polar plots have been just stupid. Are they still showing that one heart-shaped with a point?!
Wayne

 

[ZOWIE!]

Well, I just picked up a few square feet of foam at the GC flagship grand opening. I'll screw around with it over the weekend.