Connecting subwoofers and system loudness
Please remember that if you do run a sub "in parallel" with the satellite speakers* the power handling capability and low-frequency output of the satellites is not improved. The satellites will be working as hard as ever producing their full range, and the sub will not be relieving the satellites of their work at all - just augmenting them. So, the system's maximum bass output and maximum loudness is limited by the satellite's own capabilities, long before the subwoofer runs out of steam.
Originally Posted by heiner1960
To really maximise the system's loudness and bass output by many dBs you need to steer all the low bass content of the audio signal away from the satellites and to a dedicated high-power subwoofer if listening at crazy levels is what you want to do. To do this steering you'd need some sort of filter box (probably software based these days) and all the audio would pass through the box and be frequency-band analysed an then sent to the sub or satellites. I guess this functionality is built into AV receivers?
* All this means is that the sub's input is connected somehow across the amp's speaker outputs; the so-called 'high level' connection.
Alan A. Shaw
Harbeth Audio UK