06 Nov 2003, 04:06, Roy J. Tellason (1:270/615), wrote to Tom Walker:

Hi Roy.

 TW>> I just looked at a SoundBlaster card and the Mike Input is not
 TW>> Stereo. But it is an oldr card. No Fancy Sorround etc. IWhen i go
 TW>> on the Internet later today I will have to check things out.

 RJT> I know the input isn't stereo,  but the mic I have here (which 
 RJT> works) uses a stereo-type plug.  Maybe they're running power to 
 RJT> it on that extra connection,  or something,  I don't know for 
 RJT> sure.  That's why I posted about it in the first place.

LOTs of possibilities there!  If that is a 'commercial' electret mike, like
you've seen used on stage or in a studio, the third wire MIGHT be just to a
ground shield.

If it is a 'home' mike, the third wire could _still_ be just a shield lead,
especially if there is a battery _in_ the mike itself.

If there is _no_ battery _in_ the mike, then one of those leads is common
to ground on the equipment chassis, the second lead connects to B+, and the
third lead is capacitor coupled 'audio', and usually connects to a medium
or high impedance input.  No impedance matching is needed, but connecting
to a _low_ impedance input effectively shorts out the coupling capacitor.  


     Good luck...  M.

--- Msged/386 TE 06 (pre)