Re: [LAU] Audio over WIFI

On Saturday 17 January 2015 22:12:20 Ralf Mardorf did opine
And Gene did reply:
> On Sat, 17 Jan 2015 22:02:58 -0500, Gene Heskett wrote:
> > Biggest problem with the electret was the 2nd harmonic distortion
> > when driven to higher levels.
>
> Pff, are you serious? Or you just talking about one special capacitor
> microphone?

Any of them unless they are built with matching but reversed biased from
side to side stationary plates. The capacitance between 2 objects has a
square-law relationship when the distance is varied. Since its a
difficult problem trying to drive the central plate, the diaphragm, the
movable by air pressure plate when its in close proximity to a stationary
plate on both sides, they are are built only with a stationary back plate.
As long as the spacing variation is a small fraction of the overall
spacing, its not too bad, and has even been compensated for by using a FET
preamp with the correct bias etc to introduce a compensating 2nd harmonic
of the opposite polarity.

The electret condenser type has a huge advantage in this case because they
contain their own permanent charge, and its a quite high voltage, so the
spacing can get sloppily large (= cheap to make) and still have adequate
output to drive the FET buffer in it at quite low distortion. Radio Shack
used to sell, for a tenner, a pencil mike that ran the FET on a pair of
AAA cells, and it was pretty darned good for a 10 dollar mic. Way the
heck and gone better than the $60 Shure clones they had at the same time.

> _______________________________________________
> Linux-audio-user mailing list
> Linux-audio-user@email-addr-hidden
> http://lists.linuxaudio.org/listinfo/linux-audio-user

Cheers, Gene Heskett

-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>
US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/listinfo/linux-audio-user