R/E/P Community
R/E/P => Klaus Heyne's Mic Lab => Topic started by: AusTex64 on March 28, 2017, 10:41:44 PM
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What exactly are the differences between Neumann KK54 and Gefell M94? I have not had opportunity to study both. Thanks!
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We did discuss that before here: http://repforums.prosoundweb.com/index.php/topic,36984.msg535981.html#msg535981
All the age/quality issues aside, the only meaningfull difference is the backplate-holes. I can only speak from the older ones, but to my knowledge the current M94-backplates are ceramic and may have other differencies too.
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Esa,
Thansk for the link. I had forgotten about that discussion. I must be getting old...
I am wondering about the difference in sound between the two capsules. I have looked at the frequency response plots for KM54 and Gefell MV691 with M94. The Gefell shows a 5db lift in the high frequencies, which is clearly audible when recording stringed instruments, which is my primary use for these mics. KM54 plot is much more flat in the high frequencies. So does Neumann tame the capsule HF rise with the buffer?
I still need to do a side by side comparison with KM54 and my tube modified Gefells.
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... difference in sound between the two capsules...The Gefell shows a 5db lift in the high frequencies, which is clearly audible ...So does Neumann tame the capsule HF rise with the buffer?
There is no filter built into the KM54 amp I did err on this, see post below . It's easy to tame the HF response with proper capsule construction. E.g. a little less distance from diaphragm to backplate increases sensitivity and reduces the relative HF level. There are other ways to do this too.
Sound wise, I've never heard the Gefell, but the Neumann KM54 is slightly on the soft side. It does not have the airyness of the later KM84.
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(...) the Neumann KM54 is slightly on the soft side. It does not have the airyness of the later KM84.
I completely disagree. In my experience there has never been a SD cardioid capsule that has a sweeter, more complex high end response than the nickel membrane K54.
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I completely disagree. In my experience there has never been a SD cardioid capsule that has a sweeter, more complex high end response than the nickel membrane K54.
it's hard to describe sound by words, maybe we are talking about the same thing: the KM54 (I have several of those) does not have any aggressiveness, soft presence boost and tad recessed in the top octave (called air band by most) with an early roll off. Combined with the characteristics of the tube amplifier this sounds softer than most other SDC microphones to me, e.g the KM84 or Schoeps CCM4.
I have to correct my above statement about the filter: there is something in the schematic that might act like a filter, I'm not sure about the amount: C4+R1 form a frequency dependent negative feedback, the corner frequency is 4 kHz. Interestingly the amount of NFB is advised to be adjusted by selecting the value for R2. I could not find any more information about this process.
Little note: from the schematic you can see that it's important to put the calibration input to GND in the cable connector for the microphone to sound correctly. Otherwise C3 cannot shunt the NFB signal to ground, so NFB would be stronger than intended.