diyAudio (
-   Swap Meet (
-   -   Calibration mic (or parts for one) (

Spasticteapot 18th August 2008 02:25 AM

Calibration mic (or parts for one)
I'd like to buy an inexpensive calibration microphone, or parts for one. I've had a great deal of trouble finding any WM-61A capsules, and I have a feeling I'd likely make a hash of removing the internal FET if I did.

bwaslo 18th August 2008 03:09 AM

why do you want to remove the FET?
I have some capsules if you need one.

Spasticteapot 18th August 2008 05:15 AM


Originally posted by bwaslo
why do you want to remove the FET?
I have some capsules if you need one.

The internal FET, according to Sigfried Linkwitz, severely limits the performance of the microphone element. I wouldn't know, but Linkwitz is probably as good a source of info as any.

Shaun 18th August 2008 08:52 AM

The biggest performance gain of SL's mod is max SPL. It is not done by removing the FET, but by reconfiguring the connection (cutting a track). It is very delicate work, but do-able.

zlast 18th August 2008 07:39 PM

bwaslo - your email is not enabled. How much for a WM-61A ? Digikey has them but has a $25 minimum order.

bwaslo 18th August 2008 09:55 PM

The FET is the limiting element, but that doesn't mean it can work without one. (Like, a battery is the limiting element of a flashlight, but because it's not enough, not too much!)

The Linkwitz mod is good, but not easy to do. If you are only measuring frequency response at normal listening volume (and not right at a speaker cone) it isn't needed, though. The mod increases signal handling and lowers distortion (but raises noise level), the frequency response isn't affected.

You have mail...

All times are GMT. The time now is 02:02 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2