I had Studio 100 V3s. With those, weak bass was not an issue, and I think that's true with the Paradigm line in general. I agree with all of the above posts. Something must be set wrong. In addition to the above ideas....Have you checked to make sure the speaker wires are in the correct phase? Does the receiver have a crossover setting? If so, where is that set? Are the settings on the receiver such that it's sending the lows to the subwoofer output even though there's no subwoofer? And as Bob Reynolds asked, how is the biamping set up?