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Author Topic: Wrinkles in U87 capsule  (Read 1492 times)

Offline radardoug

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Wrinkles in U87 capsule
« on: May 05, 2014, 05:01:25 pm »
Opened up a U87 Ai the other day, the back side of the capsule is wrinkled badly. I contacted Neumann about it, they said wrinkling happened when the microphone was dropped. This microphone shows no evidence of drops, and I would have thought it would have to be a hell of a drop! Anyone got any comments? Is it possible Neumann sent out a mike with a wrinkled capsule?

Offline klaus

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Re: Wrinkles in U87 capsule
« Reply #1 on: May 05, 2014, 05:26:56 pm »
Wrinkles in diaphragms occur when the edge of the capsule- in this case the outer edge of one of the two diaphragm rings- makes hard, violent contact with the inside of the head basket.

A typical case: the mic is set down hard or dropped, and the capsule, due to its elastic mount, decelerates slower than the rest of the mic, and comes to a hard stop against the basket: the typical whiplash scenario.

When the edge of the diaphragm ring hits the basket, it can lose its original, perfectly round, shape and the original, even, diaphragm tension is lost in the process, forming wrinkles in the area where the diaphragm ring was hit and deformed.

In skilled hands, the diaphragm's distortion can be removed and the capsule restored to the original factory tension without any lasting damage or effect on performance of the mic.

P.S.: You can set down a mic hard, causing capsule damage, without also causing any visible body or head basket damage, especially during transport in its form-fitted case.
« Last Edit: May 05, 2014, 06:07:49 pm by klaus »
Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

Online soapfoot

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Re: Wrinkles in U87 capsule
« Reply #2 on: May 06, 2014, 09:44:20 am »

In skilled hands, the diaphragm's distortion can be removed and the capsule restored to the original factory tension without any lasting damage or effect on performance of the mic.


This bit is very interesting to me. I never knew this was possible. Obviously it's not something for one to attempt themselves, but out of idle curiosity... is the method for this (even a loose description) consider proprietary information?

Offline klaus

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Re: Wrinkles in U87 capsule
« Reply #3 on: May 06, 2014, 12:53:38 pm »
At least my approach to it is.
Klaus Heyne
German Masterworks®
www.GermanMasterworks.com

Offline radardoug

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Re: Wrinkles in U87 capsule
« Reply #4 on: May 06, 2014, 05:03:21 pm »
Thanks for the info Klaus, so I should be able to see some deformation of the outer ring?

Offline klaus

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Re: Wrinkles in U87 capsule
« Reply #5 on: May 06, 2014, 07:14:45 pm »
Yes, usually, you will see small bite marks on the edge of the plastic diaphragm ring. These will be imprints from the inner weave of the mic head basket.
Klaus Heyne
German Masterworks®
www.GermanMasterworks.com