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Experimental 1/2" high-voltage mics samples. What do you think ?
Old 2 weeks ago
  #1
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Thread Starter
Experimental 1/2" high-voltage mics samples. What do you think ?

Hello!
I've recently recorded first samples of my newly designed 1/2" high-voltage mics with 1/2 measurement capsules, similar to Gefell M221, Josephson C617 and Sonodore. Would be happy to hear your opinions on sound!

I've used modern Russia-made 1/2" measurement capsules with titanium membranes. Frequency response is flat 10-20k +-0.5dB. Amplifier is my original design, discrete class-A circuit, extremely clean, fast and quiet, headroom up to +19 dBu with the standard p48. The soundcard is upgraded RME FF800.

I've recorded an orchestra rehearsal with soloists, I couldn't hang the mics righ above conductor's head, so I've placed them 1m outside the stage, 3m high 60cm AB. Also there was takes with 90cm AB 2m outside the stage. The piano sample recorded with 60cm AB above the body edge, between the deck and lid. There is also monaural comparison between russian capsule and Gefell Mk221 capsule in the same point. All was recorded without diffraction balls, no any processing.

Wavs here:
https://drive.google.com/drive/folde...kUyRXN1b1M1NTA

The seating arrangement was a bit wrong (see on pic) along with many other things, but anyway, you'll get an impression.
Attached Thumbnails
Experimental 1/2" high-voltage mics samples. What do you think ?-orch-1.jpg   Experimental 1/2" high-voltage mics samples. What do you think ?-p1070354.jpg   Experimental 1/2" high-voltage mics samples. What do you think ?-p1070358.jpg   Experimental 1/2" high-voltage mics samples. What do you think ?-p1070359.jpg  
Attached Files

AB 90cm Ochestra 2.mp3 (4.76 MB, 827 views)

AB_60cm_Piano 1.mp3 (4.10 MB, 799 views)

AB_60cm_Yablochko.mp3 (2.99 MB, 793 views)

AB_90cm_Doublebass.mp3 (4.12 MB, 774 views)

Compar_ Gefell MK221.mp3 (2.90 MB, 774 views)

Compar_russian capsule.mp3 (2.90 MB, 774 views)

Old 2 weeks ago
  #2
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The mics sound impressive in the wav version of Yablochko, detailed, clear, maybe a bit trebly but not harsh.
Old 2 weeks ago
  #3
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Thread Starter
Thanks aracu!

Hey people! Anybody! )) 219 views, and just one comment!
Old 2 weeks ago
  #4
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Their are some basic problems with the recording technique. Also, the mp3 compression rate seems too high. So you're not
really giving your mics a fair chance.
Old 2 weeks ago
  #5
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voltronic's Avatar
 

I agree with aracu that your WAV files sound much better than the MP3s. My comments are for the WAVs.

Not sure if it is the ensemble or your placement, but the imaging seems a bit unnatural. Maybe try to narrow the spacing next time?

The bass register sounds very good to me, but the treble is very bright. Can you share measurements for the capsules you are using?

Would love to hear some samples with choir or a small instrumental chamber ensemble. Those are places where I always feel like the Josephson and Gefell mics mentioned really show their refined quality. I can't judge much from the mono comparison.
Old 2 weeks ago
  #6
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Thread Starter
I absolutely agree, the orchestra placement is too wide but not deep enough and percussion closer then it should be. Probably even 60cm AB is too much for this venue.

The frequency response of capsules is flat (see on pic) and it runs to 20k, while mk221 curve is a bit different and runs up to 18k.

Both capsules are very similar technically, the major difference is the membrane material and its tension. Titanium is twice as lighter than nickel. And membrane of mk 221 is tensioned not so hard. That's the diference I believe. For me the russian capsule sound "higher" and drier. The Mk 221 sounds gently and warmer.
Attached Thumbnails
Experimental 1/2" high-voltage mics samples. What do you think ?-curve.gif  
Old 2 weeks ago
  #7
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voltronic's Avatar
 

This frequency plot is for the Izmeri MK-265 capsule. [English Translation]

The MK-265 appears to be a direct copy of the Gefell MK 221, other than the titanium membrane which is what Sonodore uses. It actually seems a little too good to be true that the frequency response, sensitivity, and SPL are so close to the Gefell. I don't see what you're talking about regarding the treble response though - the MK 221 is specified up to 20 kHz +/- 2 dB [PDF] - again making it a very close match in measurements.

It would be interesting to see polar plots for comparison; I can't find those on the Izmeri website.

When you say "high voltage", I'm assuming you mean capsule polarization and not supply to the mic body, yes?

Finally, is this something you are simply doing for your own use, or are you planning on manufacturing and selling these mics? I think what you have sounds promising, but it would be nice to hear some more sample recordings first.
Old 2 weeks ago
  #8
Gear Head
I rather liked the clear treble and in the first orchestral piece the piccolo was very clear and excellent. Bass was very good as well. Maybe the piano music a little bright but I still liked it.

I think it's possible that musicians like a different sound to recording engineers, but I'm not saying that's wrong. Each to their own.
Old 2 weeks ago
  #9
Gear Head
Double post - no idea why!
Old 2 weeks ago
  #10
Gear Head
 

Here's the matched three I own, and they do resemble sonically Dan's MK221 mono sample more so than the MK265 mono sample. Demonstrates there's more to a mic's sound than just the frequency plots.
Attached Thumbnails
Experimental 1/2" high-voltage mics samples. What do you think ?-mk221.png  
Old 2 weeks ago
  #11
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Thread Starter
Quote:
Originally Posted by voltronic View Post
The MK-265 appears to be a direct copy of the Gefell MK 221, other than the titanium membrane which is what Sonodore uses. It actually seems a little too good to be true that the frequency response, sensitivity, and SPL are so close to the Gefell.
It would be interesting to see polar plots for comparison; I can't find those on the Izmeri website.

When you say "high voltage", I'm assuming you mean capsule polarization and not supply to the mic body, yes?

Finally, is this something you are simply doing for your own use, or are you planning on manufacturing and selling these mics? I think what you have sounds promising, but it would be nice to hear some more sample recordings first.
There are many manufacturers of 1/2 metallic capsules. The very first was Bruel& Kjaer model 4165, the next was Neumann-Gefell MK221, presently there is also Acco (USA), BSWA (China), Izmeri.ru (Russia) and others. All of them have their own versions of the same B&K design ( because it's a requirement of IEC standard), same sizes and thread pitch, same tolerances, the same flat freq curves, etc. But. Each of them has distinctive design features that have little impact on the characteristics, but are clearly audible in the sound, that's the most important.

The polar response of an omnidirectional capsule depends mostly of its size, due to acoustic shadowing. So all of 1/2 caps matching to IEC have a very similar polar response.

Yes, I definitelly want to made a complete product based on this prototype if it will causes enough interest. This is P48 FET version with 200V polarization. I'm developing this design for several years and now I've achieved very stable and clean Dc/Dc coverter, remarkable low distortion and noise (0.001% at +7dBu), outstanding speed. The circuit is fully discrete and has no negative feedback, so that sound is very natural. This circuitry could be easily ported to 120V supply. I'd want to develop a tube version also. The main issue now is make my own very musical capsules. But It's already could be used with capsules like MK221.
Old 2 weeks ago
  #12
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Quote:
Originally Posted by Dan Reso View Post
There are many manufacturers of 1/2 metallic capsules. The very first was Bruel& Kjaer
Bruel & Kjaer now has a "multi-field" mic (no. 4961) using a 1/4" capsule, with 20 dBA self noise.
Old 2 weeks ago
  #13
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Thread Starter
Quote:
Originally Posted by aracu View Post
Bruel & Kjaer now has a "multi-field" mic (no. 4961) using a 1/4" capsule, with 20 dBA self noise.
With help of minimal shadowing of body + 1dB hf boost they achieved the frequency curve that remains within -3 dB even in diffuse field. 20dB self noise looks promising, better than DPA 4090.
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