20Hz: 114dB at 4.5% THD. I did not push any further, as the panes in my windows were moving about 1/16" at the time. I think they would have broken if I went further. Above 20Hz, you can get damned near as much as you want dB-wise, all clean. Basically, from 16 or so Hz on up, you have strong bass, from 20Hz on up, INSANE bass.