question re: poor bass response

Apologize in advance if this is a naive question. Unless they are played very loud, I have been a bit disappointed in the bass response from my Sonus Faber Concertos driven by NAD C370 integrated; source: Arcam cd92. However, at reasonable sound levels, the volume control on the amp is positioned only about 8:30 - 9:00. Is it possible that I'm underpowering the speakers when they're played at lower volume (sensitivity of speakers is 87dB, 1W, 1m). Would bass response improve if I switched the jumpers to the variable pre-outs and reduced the gain to the power amp, such that more power would be required to achieve a given sound level?