Low level listening

I have long used Quad stats and a few years ago, had my '57s restored by Electrostatic Solutions. You don't have to play them loud (in fact, they will not play at jet take off levels) to get the musical information. I use them in an all vintage tube system that has been brought to spec with fresh old stock glass.

By comparison, my main system, horns and SETs, can also deliver the musical information at low db levels. That system can play loud but I often listen at modest levels. (To get the woofers to energize the room, you have to give it some power). 

In comparison, I think the Quads act as a filter- they aren't as efficient and seem to give a warm sheen to most music- the horns are extremely revealing, more of a microscope on the music. I think, on balance, despite the '57s legendary transparency, I'm actually hearing more musical information with the horns than the Quads, but the latter sure are nice. Maybe it is the tube complement on the Quad system too compared to what drives the horns. (More "old fashioned" v. modern). For me, it was a bit of an epiphany, given that I've always considered the Quad "transparent." 

One of the other factors-- didn't see it mentioned- is the level of ambient noise in the listening room. My room, without adding additional window treatment which I have- registers in the very low 30 dbs, "C" weighted-- I'm on a quiet residential street with little traffic. 

That translates into even more musical information being revealed by the system without having to compete with a noisy background. And is a pretty simple measurement to make and take steps to address, if necessary.