Can headphones frequency response change with volume?

Looking at the Equal-loudness contour, it does seem like the bass increases at higher volume.

Quote:

Originally Posted by bcasey25raptor 

For example i noticed that as i turn my m50s up they get more bassy and the mid go further behind the rest of the music. Highs are also more extended. This might all be mental but is it possible for headphones frequency response to be altered as the volume is increased/decreased.?

It's more noticable on certain headphones IMO.

http://en.wikipedia.org/wiki/Fletcher%E2%80%93Munson_curves

http://en.wikipedia.org/wiki/Equal-loudness_contours

Yes, well-known effect of human physiology. Probably has more effect on individual perceptions of neutrality in headphones than we think. One person's "recessed mids and boosted bass and treble" is another's "neutral and well-balanced" if one listens at 93 dB and the other listens at 68 dB.

Definitely..... there will be some subtle or not so subtle changes in sound output, and more importantly, differences in how the music is perceived, for example if driven loud enough, a veiled headphone may seem less veiled and bass impact will increase since more air is moved as compared to lower volumes.

In my experience the answer is Yes!...as well the hps FR will chance with different audio sources.

short answer is yes.

a few things can change with increased volume.

bass requires more power because the cone needs to move in and out more.

but

with more power for the bass also brings with it more power to tighten the timing.

these two things together can be all that is needed for a change to be noticed.

headphones are the first place to look for a single speaker trying to do it all.

because of the work effort inside the speaker, it isnt a rare thing to see changes with volume increasing when used with 'outside' amplifiers.

outside amplifiers are basically lower quality amps that are designed around a specific output level instead of the whole volume dial.

that is how they get their 'upgraded' sound, because they take quality away from other portions of the volume knob.

when more voltage goes into the capacitor bank.. the ESR value changes, and that changes the timings.. making the voice coil react differently to the electricity.. and that is the change in frequency response you hear.

(could be resistors causing the change too)

I listen quietly. So quietly that the overpowered, overgained Xenos 3HA amp I owned couldn't get past its low level channel imbalance with any of the cans I owned at the time (Bose QC2, Sony MDR-SA5000, Sony MDR-7504, Sennheiser HD497, old khaki Koss) so it was kind of useless to me. My Cute Beyond is much better in this respect.

Anyway, I sometimes have to remember to take a lot of user impressions (amps, cans, and the technical side of recorded music) with a grain of salt given the knowledge that I'm a quiet listener.

Considering Etymotic ER-4PT and Audio-Technica ATH-ANC7B actually, for the increased isolation...