naturerecordists
[Top] [All Lists]

HF noise in MKH 20s

Subject: HF noise in MKH 20s
From: "Dan Dugan" dandugan_1999
Date: Thu Jan 19, 2012 6:29 pm ((PST))
A few weeks ago someone, I think it was David Brinicombe, mentioned observi=
ng HF noise in Sennheiser MKH 20 microphones. I've noticed it too, when loo=
king at a spectrogram of a quiet environment.

This morning we did a comparison of a 3032 next to an MKH 20 on the carpet =
of an interior room, covered with some blankets. The diffuse-field HF boost=
 switch was in the flat position. I used the preamps in a Sound Devices 744=
T. I posted an expanded-scale picture of the resulting spectrum at:

http://www.dandugan.com/downloads/Nature_Sounds_Photos/AT3032_v._MKH_20_noi=
se_via_744T_preamps.png

Red is Sennheiser, green is Audio-Technica. The down-sloping curve on the l=
eft is obviously ambient noise. I tried to match the levels at around 500 H=
z. I believe that above 1K we are probably seeing mic self-noise plus pream=
p noise. The "hiss" from the MKH 20 is obvious. I put hiss in quotes becaus=
e I can't hear this noise at all. It isn't trivial however. I see that up-s=
loping top end in recordings from quiet locations.

The tonal artifacts in the 3032's spectrum, especially in the range 400-1KH=
z are curious. They could be from the mic or the preamp, not investigated y=
et.

My first guess is that the MKH 20 might be equalized in its electronics to =
compensate for a naturally rolling-off HF response of the capsule.

-Dan





<Prev in Thread] Current Thread [Next in Thread>
Admin

The University of NSW School of Computer and Engineering takes no responsibility for the contents of this archive. It is purely a compilation of material sent by many people to the naturerecordists mailing list. It has not been checked for accuracy nor its content verified in any way. If you wish to get material removed from the archive or have other queries about the archive e-mail Andrew Taylor at this address: andrewt@cse.unsw.EDU.AU