Mechans, as Mulveling indicated my calculations are consistent with the published specs, shown near the bottom of this page. As he points out, though, it certainly seems possible that the max power handling number reflects how much power the headphones are rated to handle continuously, and that they may be able to handle considerably more on brief musical peaks. And/or perhaps that spec is very conservative, and has a lot of margin built into it.
Either way, though, the relation I described between power requirements for the phones and for the typical speakers I described remains valid, assuming the sensitivity and impedance specs are accurate.
FYI, the derivation of the 99 db figure is as follows:
The sensitivity spec for the phones is 97 db/V, which means that 1 volt in results in a 97 db SPL. Impedance is 32 ohms. 1 volt into a 32 ohm resistive load corresponds to 31.25 milliwatts (mw), based on (Vsquared/R). The 50 mw maximum power spec is approximately 2 db greater than 31.25 (based on 10 x log(50/31.25)). 97 db + 2 db = 99 db.
Regards,
-- Al
Either way, though, the relation I described between power requirements for the phones and for the typical speakers I described remains valid, assuming the sensitivity and impedance specs are accurate.
FYI, the derivation of the 99 db figure is as follows:
The sensitivity spec for the phones is 97 db/V, which means that 1 volt in results in a 97 db SPL. Impedance is 32 ohms. 1 volt into a 32 ohm resistive load corresponds to 31.25 milliwatts (mw), based on (Vsquared/R). The 50 mw maximum power spec is approximately 2 db greater than 31.25 (based on 10 x log(50/31.25)). 97 db + 2 db = 99 db.
Regards,
-- Al