I get a red light on the back panel labeled power. No green light. I don't think the PV 600 is working but when I run the channel check through my Pioneer THX receiver I hear sound. Any thoughts?

The PV600 and PV400 have auto-on circuitry that turns the subwoofer on when a signal is presented, and turns off if no signal is detected for 15 minutes.

http://www.retrevo.com/support/Boston-Acoustics-PV600-Subwoofers-manual/id/522dj484/t/2/

Not knowing which Pioneer receiver you have I have dropped in the steps for No Sound from Subwoofer:

• Check that the subwoofer is connected properly, switched on and the volume turned up.

• If your subwoofer has a sleep function, make sure it is switched off.

• Make sure that the Subwoofer setting is YES or PLUS (see Speaker Setting on page xx).

• The crossover frequency may be set too low; try setting it higher to match the characteristics of your other speakers (see Speaker Setting on page xx)

• If there is very little low frequency information in the source material, change your speaker settings to Front: SMALL / Subwoofer: YES , or Front: LARGE / Subwoofer: PLUS (see Speaker Setting on page xx).

• Check that the LFE channel is not set to -80dB , or a very quiet setting (see Bass Peak Level

on page xx).

• Check the speaker level settings (see Channel Level on page xx).

Regarding the Large vs Small assignment of speakers, what they mean isn't so much the physical size but the ability to handle real bass. Large if Yes.