[stephenb1]

Hi stereo sub outputs seem to be very rare on av amps but the top and near top of the line Yamahas do have them and sometimes a mono as well.

The sub channel on Yamahas is derived from the front and rear mixed together, and the mono sub from all channels when listening to music and movies from the LFE channel as outlined in the Yamaha manuals.

The sound with true stereo subs is so much more rhythmical and rounded as appose to two mono LFE subs IMO as two monos can sound a little monotonous and boring after a while during A to B testing.

I have tried the front outputs of my Yamaha A1 set to large via a behringer Cx-3400 crossover and found the output near identical to the sub left and right outputs, so as explained in the last reply it would be fine to use the main stereo signal for the right channel and the left as normal from LFE channel, or both subs from the front outputs set to large or if the front outputs are in use maybe zone 2 output.

The crossover is very helpfull with added output for better control of the subs so maybe you could purchase a behringer cx-3400 or cx2310 as they are very cheap and great value for money, or a dcx 2496.