In Reply to: help needed with intercom circuit posted by Seamus O'Donnell on 10/22/00 at 6:52 PM:
The LM386 data sheet at http://www.national.com/ds/LM/LM386.pdf shows only using the device with an 8 ohm load, so trying to drive two 8 ohm speakers is probably not a good thing. You might want to consider the LM4873 at http://www.national.com/ds/LM/LM4873.pdf instead.
A user hearing his own voice is called a "sidetone" and can easily be done by feeding a sample of the user's spoken audio back to his own headphones.
John Dunn - President