Why more bass subwoofer into power conditioner

I have found the same to be true of the gear I plug into my balanced power conditioner from BPT.  More bass.  This is consistently the case as I change gear and the years go by with my BPT. 

Lots to be said for balanced power. Lots.

Worth looking at the incoming and outgoing voltage.  Sometimes the transformer windings are designed to up the outgoing voltage a little. Usually a good thing.

OTOH, digital power supplies are usually pretty tightly regulated.

"Sometimes the transformer windings are designed to up the outgoing voltage a little. Usually a good thing."

My isolation line conditioner bumps up the voltage by almost 2 volts when compared to the incoming wall voltage.  

Like Erik pointed out, the power conditioner is probably delivering more voltage and current to the subwoofer than the circuit can. This is due to the conditioner design to “wow” you with what could otherwise be accomplished by swapping out the filter capacitors with larger value units and supplying the subwoofer with a very slight voltage boost from a step up transformer. 

There is no magic here. It’s just simple electricity. Some amplifier manufacturers design a switch into the power supply to allow the amplifier to run off of a higher voltage tap from the power transformer when driving a higher impedance load. This has the effect of delivering more current and hence power to the load. 

By by the way, there is no such thing as a balanced 120 volt circuit in North America. That is physically impossible with split phase power delivery, which means the 120 volt feed is derived from the neutral conductor and one of the two hot conductors. Neutral is bonded to ground at the main service panel in accordance to electrical code. Thus, any reasonably modern device that’s designed to connect to a 120 volt circuit will have a polarized plug so extra safety precautions can be made (such as power switch and main fuse being on the hot conductor). If you feel compelled to use balanced power, your equipment would need to handle 240 volt power, which is truly balanced from a neutral and thus ground perspective. The only up side to running with 240 volt equipment is that if the whole house used only 240 volt equipment, the breaker panels we use would always be in perfect balance from a load perspective. But then, the neutral conductor would be redundant and probably removed for economic reasons, and then one side of the 240 volt feed would have to be bonded to ground for safety, and we’d be back to square one all over again.