How do you listen?

Some tracks sound best at a certain volume for the simple reason they were mastered to be that way. This is due to our hearing not being linear but corresponding to equal loudness contours mapped by Fletcher and Munson. We do not hear all frequencies equally well at all volume levels. Low bass and high treble in particular need to be at a fairly high level to be heard at all. This is why the Loudness control used to be so common. All audiophiles should know this but whether they do or not all recording engineers certainly do.

You are perfectly right ...

But we must not so much compensate this difficulty of equal perception between frequencies with higher volume than with an adequate room acoustic control to make easier the clarity of perception...

The better a room is controlled relatively to the speakers/room response the less we need to increase the sound volume to perceive details and music..

When I say I listen “very loud,” that for me, at peak, is about 80-85db.

I spent a bunch of time trying to determine if there was a “right” volume (for classical). I attend the symphony regularly. I found there generally is. You want the passages which begin quietly from total silence with single quiet instrument to be audible and the crescendos of the full orchestra to reach saturation (my seats are 7th row center). So with those boundaries I adjust my system to listen to classical.

I typically listen to other music arround 70db unless it is rock then a bit higher.

80-85db on an iPhone app is my “loud” also.  

Didn't even know you could get 85dB out of a iPhone. New Pro, I guess.