Hi, I just assembled a "Stereo Listener" kit from Velleman (PMK136). But the thing really needs its bass attenuated to be useful in the application I planned for it. It is based around the TI NE5532P "Dual Low-Noise Audio Amp" chip and uses two generic electret cheapo mics.
Anybody here know which components to sub or add in order to help this otherwise useful circuit?
I'm going to cross-post this to s.e.basics too.
Thanks.
--Maxx
Assuming it has coupling capacitors somewhere in the signal path, just lower the value of those. From the standpoint of low noise, it would be best if the caps you replace are at a point of relatively high level (avoid doing it with caps at the input). If you're savvy enough to know what the load and source resistances around those caps are, you could even figure the response pretty accurately...
Cheers, Tom
Posting a schematic somewhere will get you help from all of the folks who can read schematics but don't want to dig out the info on that particular kit -- just a link to Vellman's schematic if they have it posted will be enough.
-- Tim Wescott Control systems and communications consulting http://www.wescottdesign.com Need to learn how to apply control theory in your embedded system? "Applied Control Theory for Embedded Systems" by Tim Wescott Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
Thanks for the quick response! I've found a schematic at this location:
I spent some more time listening to the signal coming out of this thing again, and I think I was hallucinating. What's really needed is a high freq cutoff just above the human vioice. With this circuit you can hear every insects whine and the whoosh of any airflow in the vicinity. The sibilance of normal speech is almost painful.
Thanks for any help.
--Max
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