spheres for mikes (neumann M 50)

[al burn]

if you know about the neumann m 50 with it's 40mm sphere and the 12mm diaphragm built with in, you might be able to answer my question:

if i make a slip on sphere for my mikes (similer to the Scheops) how would it change the polar patern.
I know it's ment to be used with omni pressure transducers but, what if i use it on a pressure gradient like a cardioid.

i was thinking of making some out of wood and sliping them over my oktava 012's

any ideas?

[joel hamilton]

I love using physical spaces to affect directivity in mics. This is not a new concept, as your neumann example illustrates.

Cool idea. Makes me inspired to mess with this more. I used to use little wooden boxes of various sizes to "tune" the frequency response of SM57's on the floor as room mics on drums.

I seemed to wind up with boxes that were like 5x5x7 inches, open side facing the drums with the 57's pointing into them, away from the drums.

This gave me a slightly darker sound, that seemed to sit better with the direct mics, while giving the track a nice sonic "fingerprint."

[al burn]

sounds kinda' like a parabolic mic but, I was talking about the sphere being built in/on the mic. think of a lolly pop with the diaphragm flush with the sphere's surface so that, when you look at it on axis the mic looks like an eye ball.

[joel hamilton]

I know what one you were talking about, there are a few mics that use that same principle. The example I cited was just my super ghetto way of "focusing" the sound.

I didnt have any pressure gradient omni's at the time.

Regardless, your pst inpired me to break out some weird little boxes for my next tracking session. I havent used them in a long time.

I think your idea of making some for yourself Is awesome.

Good luck, I would love to know what you come up with!

[brew]

think about it. a cardioid pattern mic is the combination of pressure (omni) and pressure gradient (figure 8). this "mix" is created by the holes on the side of the capsule (which is the pressure gradient aspect of the mic). if you cover those holes (such as with a sphere in your case) you effectively eliminate the pressure gradient part of the microphone, so you'd just have the pressure left. your new polar response should be somewhat omnidirectional.

[al burn]

thats what I figured and wanted. I was hoping to change my mic into an omni but retain the directional characteristics above 1K