I'm replacing what I think is a bad amp with an old xtant 403a to drive channels 3/4 to the underseats. Using kaigoss's setup in my 335xi/Logic 7. Not getting sound from the underseats during signal check.
Perhaps I've set the xtant input gain too low? Based on the xtant manual:
I've tried input gains of -10dB and +10dB. Output gains set at 1/4. Using balanced input, RCA outs from the MS-8.