I have the empeg working fine into 3 amps; 1 for the fronts, 1 for the rear fill and 1 for the sub. I have a speaking nav system and also a GSM phone car kit. I would like to feed the GSM and nav output to both channels of the front amp in parallel with the empeg.

So far I have put a potentiometer across the nav speaker level output with the slider connected to the signal line of the left speaker. This allows me to dial in the voltage to this channel and it all works well. The empeg hushes and the nav system can be heard above the music.

I would ideally like to output this signal (and the phone signal later) to BOTH channels but if I do this by linking the left and right input it works but obviously I loose the stereo signal from the empeg as both channels are bound together giving mono.

Question: What components would be required so that the Nav mono output can be fed into the 2 separate L-R channels without binding them together?