OP is that main out? if you have two pairs of mains output, and a volume control on one. I suggest it was for bi amping horizontally and controlling the lows and highs on the fly... or one pair for sub duty, the other full range. There are a few things you could do. The fact is you can only go DOWN in volume and up to the maximum of the main volume control..
Like I said good for bi amping, when one anp it to hot for the app..
Regards
Like I said good for bi amping, when one anp it to hot for the app..
Regards