Okay, so how does a guy control the bass on the towers like the SX-6300 or SX-8300?
Let's say you have an AT2002 2Ch amp and Parasound P5 preamp with Subwoofer output (LFE) and a pair of SX-6300/R.
This is one way.
You would need an extra amp and the LFE signal that would normally go to the sub in a 2.1 setup.
The extra amp could be any spare amp, preferably with volume control like a sub amp such as the Dayton SA230 ($200) from Parts Express. This amp can power both tower's bass if you wire in series. Otherwise, you would need 1 amp for each tower.
Dayton Audio SA230 230W Subwoofer Amplifier
1. Remove the jumper cables on your SX-6300.
2. Connect the speaker cables from the AT2002 to the TOP speaker binding posts of the SX-6300.
3. Connect the LFE output from your Parasound P5 to the LFE input of the Dayton SA230 amp.
4. Connect the speaker output of the Dayton SA230 amp to the BOTTOM speaker binding posts of the SX-6300.
Now you have actively bi-amped the SX-6300. You control the bass amount of the SX-6300 with the Dayton volume knob.