Fred did say from memory but if you draw a line across at ~88db that little peak around 35hz is the +/- 3db point claimed, a spread of 6db, which is how the claims are usually done. Axiom actually claims 34hz +/- 3db for the M80v3.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70