I have one of these green large diaphram Russian mics. I had put it away for a
while because one time it seemed to be emiting spurious crackling sounds. I've
been meaning to send it somewhere and have it looked at. Tonight I set it up
and listened for the crackling but didnt hear any. Now I'm not sure whether the
mic was actually the source of the noises or not.
Anyway, at one point I tapped lightly on the body of the mic and noticed a
quite loud resonance coming out of the speakers. I measured it at about 112 Hz.
I dont know whether an acoustic event like drums or such would excite this
resonance enough to color a recording but it seems quite possible. I tried
holding the mic's body in such a way as to dampen it but it didnt seem to have
any effect on the loudness or duration of the ringing (its quite sustained, I'd
say about 1 second).

Does anyone else have this mic? If so, have you noticed the resonance? Is it
something I should to try to fix? Is this a known problem with this mic? I know
that some Oktava mics are known to have resonance problems. Is this a Russion
thing? I was going to stuff some foam into the body but I couldnt get the tiny
screws holding the body together to come loose.

Any ideas?

Garth~



"I think the fact that music can come up a wire is a miracle."
Ed Cherney

Garthrr wrote:
I have one of these green large diaphram Russian mics. I had put it away for a
while because one time it seemed to be emiting spurious crackling sounds. I've
been meaning to send it somewhere and have it looked at. Tonight I set it up
and listened for the crackling but didnt hear any. Now I'm not sure whether the
mic was actually the source of the noises or not.

Keep it in a box with some silica gel and keep the diaphragm dry.

Anyway, at one point I tapped lightly on the body of the mic and noticed a
quite loud resonance coming out of the speakers. I measured it at about 112 Hz.
I dont know whether an acoustic event like drums or such would excite this
resonance enough to color a recording but it seems quite possible. I tried
holding the mic's body in such a way as to dampen it but it didnt seem to have
any effect on the loudness or duration of the ringing (its quite sustained, I'd
say about 1 second).

Yup. It's a combination of the body ringing, and of the head mounting
assembly.

Does anyone else have this mic? If so, have you noticed the resonance? Is it
something I should to try to fix? Is this a known problem with this mic? I know
that some Oktava mics are known to have resonance problems. Is this a Russion
thing? I was going to stuff some foam into the body but I couldnt get the tiny
screws holding the body together to come loose.

Try RTV on the inside of the body. I'm not sure offhand how to reinforce
the head mounts... on some of the Nevatons I have taken JB Weld (a filled
epoxy putty) and covered the mounting frame with it to stiffen it and add
mass.

Any ideas?

Another possibility is that the rubber shockmounts have gone hard, and so
the shock mounting is now tuned to a much higher resonant frequency than
it should be. Take the grille off, press the shockmount with your fingernail
and see if it cracks. If so, it's bad.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."