PVC or mylar membrane?

Hi,

I got my 5840 plate fed, self bias (almost G7) circuit finally working. It's time to swap the stock capsule of the body donor to something better. I've decided get a Thiersch SWT 7.

Have any of you had chance to compare their PVC and mylar skin capsules? Is there a noticeable difference in sound (if you don't count the aging effect)?

I've heard that shootout, but there's no Thiersch built PVC capsule, only reskinned original M7 (which I BTW liked 2nd best in this shootout). I doubt Thiersch capsule sounds exactly the same.

Hi,

  at the end of the day, you are building a "new" mic, not refurbishing a vintage one. All m7 and KK7's have a Family signature in my experience. Who is to say which will sound best with your partcular tube/tranny/ casing combination? I have a huge faith in Mr Thiersch. He has reskinned many capsules for me, and supplies large amounts to my chum who repairs mostly tube mics for his living. I have never actually heard an original m7 as it should be, since pvc deteriorates. They always sound great when re-skinned. I would hazzard a guess that the mylar is a tad smother and more extended at the top, and a tad warmer at the bottom. I have not, however, made a direct comparison.



      ANdyP

There is a difference in the thickness of the PVC vs. polyester membrane. This will, of course, affect the response to the very highest audio frequencies. This is why the polyester has a brighter or more transparent sound. In my listening, PVC will perform best in the case of recording a male vocalist and less well when one wants to make recordings where the phase relationships of the audio signals and particularly the "imaging" band needs to be reproduced faithfully. That was one of the motivations for the introduction of the U67 with the K67 polyester capsule.

strangeandbouncy said:

Hi,

  at the end of the day, you are building a "new" mic, not refurbishing a vintage one. All m7 and KK7's have a Family signature in my experience. Who is to say which will sound best with your partcular tube/tranny/ casing combination?

Click to expand...

That's a very good point.

burdij said:

PVC will perform best in the case of recording a male vocalist and less well when one wants to make recordings where the phase relationships of the audio signals and particularly the "imaging" band needs to be reproduced faithfully. That was one of the motivations for the introduction of the U67 with the K67 polyester capsule.

Click to expand...

Interesting, considering that U67's electronics with negative feedback are quite far from a faithful phase relationship philosophy, if I understand correctly.

pasarski said:

Interesting, considering that U67's electronics with negative feedback are quite far from a faithful phase relationship philosophy, if I understand correctly.

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I believe that this assumption, in general, is incorrect. The theory behind negative feedback shows us that systems that incorporate negative feedback actually reproduce the signal more accurately, both in phase and in harmonic content, than a system that is not controlled ("open loop").

The feedback system and the capsule design in the U67 was created as a system to produce a microphone which recording engineers of the day, responding to the needs of FM broadcasting that needed a more accurate (less "colored") microphone, could use to record classical instruments at a distance.

burdij said:

pasarski said:

Interesting, considering that U67's electronics with negative feedback are quite far from a faithful phase relationship philosophy, if I understand correctly.

Click to expand...

I believe that this assumption, in general, is incorrect. The theory behind negative feedback shows us that systems that incorporate negative feedback actually reproduce the signal more accurately, both in phase and in harmonic content, than a system that is not controlled ("open loop").

The feedback system and the capsule design in the U67 was created as a system to produce a microphone which recording engineers of the day, responding to the needs of FM broadcasting that needed a more accurate (less "colored") microphone, could use to record classical instruments at a distance.

Click to expand...

Makes sense. Every U67 recording I've heard has sounded very accurate, non colored. I don't know where I've gotten my assumptions about NF. Maybe it's because I find U87ai to have some phase issues. Don't know if they're related to NF however.

But on topic again, I think I'll go for mylar. Sounds great in that shootout, and also I want to believe in advance of technology (And they are dirt cheap at the moment BTW.)