[BFay]

None of that comment seemed unreasonable to me - I've had large over-ear sets of headphones that require me to turn the volume up pretty high. It takes more to drive them, that's why some people own headphone amps.

Compare that to IEM's like the Sennheiser cx 300 - 5% of max volume at my computer might be too loud.

And it would surprise me if headphone usage at reasonable volumes is worse than going to loud concerts, even if you use headphones for long periods of time. If I'm at a concert or a loud bar for an hour or two, my ears feel really fatigued afterwards, everything seems quieter. I've never turned up headphones loud enough to experience that.

[seanp2k2]

If anyone is curious, this is what the sensitivity measurement is on headphones: https://en.wikipedia.org/wiki/Headphones#Sensitivity

TL;DR "The sensitivity of headphones is usually between about 80 and 125 dB/mW and usually measured at 1 kHz." and note that since dB is logarithmic, every 6dB is 2x the energy (human-perceived "doubling of volume" is typically ~10dB; see also: https://en.wikipedia.org/wiki/Fletcher%E2%80%93Munson_curves )