I went to Norwegian distributors website which has quite a lot of writings about this sub, not so much about specifications though but this is what's stated about techspecs for B&W PV-1D
* 400W Class D amplification (no more info)
* -3db at 7.5 Hz and 450 Hz
* -6dB at 6.5 Hz and 570 Hz
* 4 different Bass eq presets (no more info)
Bass boost is continually adjusted so it's automatically decreased when SPL goes up, so in practice the -3dB point at 7.5Hz is probably like chasing the gold at the end of the rainbow
B&W is not know to make face specs, just wonder at which SPL's the above stated specs could be, probably only at very very low SPL levels like 35dB
.....