The properties of a room that affect the quality of a sound source in the room. (i.e., reverberation, resonance modes, etc.)
"I want you to know that I am a tough critic, so I put you guys to the test. As soon as I received the CD in the mail, I inserted it into my player, and instead of just listening to it out of my speakers I put on my head phones. I figured if you guys can produce what you say you can, the head phones would really tell. I have to say that I could ..."