If it refers to amp output, it means you can only expect about 6 more dB above those values at 100%... meaning it will only do 88dB at 30hz and 80dB at 20hz. Not the worst I've seen by any means but not enough to blow your hair back.This is pure nonsense.. 25% volume can mean anything…
And now that I see the whole image, the 125dB with subwoofers is probably with the whole system going full out with either pink noise or at a certain resonance frequency...
Honestly I'd put as much faith in these numbers as I would single-ply toilet paper...