Question about Figure8/capsules/87 style mic

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Spiritworks

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Aug 6, 2009
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I built an 87-style mic from a complete kit from Dachman audio. As expected, it was a fun build with a decent result, but not a "wow" moment. A bit bright, which I attributed to the capsule. So I bought a capsule from Beezneez to replace the kit one, just to see if there was an improvement. I highly expected there would be, but alas, things didn't change all that much - if at all.
However, with the Beezneez capsule installed, I noticed that the rear plate, in figure 8 mode, seemed much better than the front - more full range, less fizzy....
I would expect capsules to be balanced on both sides. If I flipped the capsule around and re-soldered it, I would say there was an improvement when in cardiod.
Any thoughts about why this is, what I should look for? The only thing that comes to my mind is that there is a bias adjustment in the mic circuit. Does that have to be tweaked for the new capsule? I have built almost a dozen mics from various sources, all of which we use all the time in the studio with good result, so this one is a puzzler.
Thanks
 
In Fig-8 you'll get even more proximity effect than in cardioid. Might that (in addition to the out-of-phase-ness) contribute to some of the differences you're hearing?
 
The point is that when you are listening through headphones, you hear a mix of the sound 'in your head' and the sound coming out of the headphones. This can give a misleading impression, because in figure-8 the rear membrane has a different phase than the front membrane. Usually when the sound coming out of the headphones is 'in phase with the sound in your head', it sounds better.
Here is a video that explains it:
http://www.vansteenisaudio.nl/Audio/Neil_Cappellino.mp4
 
Countless comments about capsules having better/worse sides, including Neumann. Neumann specialists who pick the best side and put it on the front during service or replacement.
 
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If I flipped the capsule around and re-soldered it, I would say there was an improvement when in cardiod.
Maybe clarify for some of the replies here if you recorded the front and back, both setup in cardiod, and noticed a difference versus the other assumptions

I agree with EMRR in that case you have a capsule with variation in the sides. I would contact Beezneez.

Years ago, I compared a bunch of capsules for front/back matching by testing the null rejection in fig8 and found 'budget capsules' had MUCH worse rejection than the boutique capsules I tested (Thiersch M7, TC Ck12, maybe a k7 Beezneez, if I remember correctly). A boutique capsule should not have a noticeable difference IMO without there being a defect.
 
So the bias adjustment in the circuit is of no concern?
It seems that I may get better results if I flip the phase on the mic preamp.
Some interesting things to look into. Thanks all for your input.
 
So far I have not recorded anything. This is just my impression while listening through headphones
The point is that when you are listening through headphones, you hear a mix of the sound 'in your head' and the sound coming out of the headphones. This can give a misleading impression, because in figure-8 the rear membrane has a different phase than the front membrane. Usually when the sound coming out of the headphones is 'in phase with the sound in your head', it sounds better.
Here is a video that explains it:
http://www.vansteenisaudio.nl/Audio/Neil_Cappellino.mp4
In Fig-8 you'll get even more proximity effect than in cardioid. Might that (in addition to the out-of-phase-ness) contribute to some of the differences you're hearing?

Ahem... 😉
 
That makes sense, thank you. However, this doesn't seem to occur with any of our other mics while monitoring the same way. Can we assume this is the only capsule that is out-of-phase? Besides using the phase button on the pre-amp, how can this be corrected?
 
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