i have a 2 channel 400 watt amp and i only use 1 channel cuz i only have 1 sub. i was wondering with 1 channel could i connect both of my back speakers to it. if yes would the picture i drawn below be correct? please help me thanx. also which setting would i set of my crossover??

 

can you hook up the rear speakers regular, 1 on each channel, then bridge your sub between them

 

What kind of amp, [make and model] is it not bridgeable into a 1ch amp for sub use.

As there is probably only one x-over switch, for it to work properly it would have to be set at LP, [low pass] but running your read speakers on low pass is not going to work, you may be able, [depending on amp] be able to run it in "tri mode" left and right , [2ch mode] to the rear speakers and bridged mono for the sub, [a passive x-over, low pass, would be needed for the sub at least, and maybe high pass for the rear speakers] 94