What makes a speaker perform well at low volume?

Well,

1st thing, study the Fletcher-Munson curve to help define how your hearing changes at varying dB's, then measure the average spl at which you listen to music. Look at the chart.

2nd realise that equalization is needed, whether the speaker has it subtley built in itself or something as coarse a loudness button on your amplifier.

All of the answers above to one small degree or another are correct but the true reality is a speaker that has boost in the highs and the bass will sound the best at low volumes period. Those speakers will achieve the nearest flat response to your ears relative to normal listening levels at lower listening levels.

A sensitive speaker and amplifier have little to do with the overall performance unless they address the F-M Curve in some fashion at the levels you are listening too. Address your hearing and background noise in the room and you will solve the problem of listening at low levels.

An decisive solution to your problem is the Accuphase DG-38. This will solve all your problems, at normal and low listening levels.

Thanks for the comments Trelja,

This thread was beginning to worry me, I was getting the feeling that this was a complicated problem LOL! With only mythical and very expensive solutions.

I can't believe all the gyrations people think they need to go through to solve a simple problem. :)

"Root Canal Audio" is a phrase a friend turned describing most of what is written above.

thank again T