solderdude
Grand Contributor
Yes, I had considered that, but then I thought you'd still be able to detect it was somewhat insufficient in bass, and certainly different to say a Stealth played at any volume, so it seemed a surprising statement to me. I also think most headphone amps reviewed on this site would be able to get the HD650 to loud enough levels that the whole Fletcher Munson Curve thing is overcome.
Consider that this is when using tones. In music the mids and treble are much lower in level and thus you need to view the curves that way
In music bass notes are louder than mids and are mixed at average levels (total music energy, not mids or treble) so that is why at louder levels the bass still sounds relatively louder.
There's not much difference between 90dB and the louder levels, and you could probably make the same case for the 80dB curve or at least the curves between 80dB and 90dB that aren't pictured. Pretty much all headphone amps can drive an HD650 to 90dB I would think.
To 90dB sure, even a phone can make it reach 100dB.
It becomes different when you want to play impressively loud (115-120dB peaks).
You must realize.... Amir wants his earlobes to vibrate. You cannot do this with a phone and having the idea (and practice) of going loud with plenty of volume range left makes for a more impressive experience (when cranking it up)