[krytie75 (OP)]

With the exception of some pieces of music which should be played quietly for obvious reasons, most regular modern music is far more enjoyable when played just below the 'it's too loud' threshold than when played at lower volumes.  Several of my friends have mentioned this too.  I was wondering if there's an physiological reason for it?

[RD]

The frequency response of human hearing varies with loudness ...

The first research on the topic of how the ear hears different frequencies at different levels was conducted by Fletcher and Munson in 1933. In 1937 they created the first equal-loudness curves.

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

i.e. the perceived frequency content of music is dependent on its volume.

If the music was made to be listened to loud it will sound tinny when turned down.

[techmind]

As RD says.

I understand that the reasoning behind the "loudness" or "bass boost" button often found on consumer audio players is to allow the listener to achieve the thumping bass effect at low volumes which would normally only happen at high volume.

[SeanB]

Generally live recorded music sounds best when played back at a similar loudness level to what it would sound like when "live", as most musical instruments change their tonal values when played at different volumes. A piano is an example of this that is easy to get and demonstrate.

About the only instrument that does not show this is the bagpipes, they have no volume control aside from really loud!