Here is a brief video I took last night showing SPL peaks.

This is using two of the "centers" at 10 feet back coming off a 150 watt amplifier with headroom to spare.

As you can see, we are hitting 110dB peaks with 2-channel music, only 2 speakers, and there is no compression or distortion and bass is extending down to the very low 30's.

No subwoofer connected and the SPL meter used is a professional model and fully calibrated.

http://youtu.be/vY2XV8oqSqE