Standing waves

Standing waves are everywhere, well almost. Get a hold of an SPL meter and a test CD with test tones. You will find all sorts of standing waves, echoes, peaks and reflections that interfere with the pure unadulterated signal from the speakers. Everywhere you find a sound pressure level at least say, 4 or 5 dB above the average sound pressure in the room you got a problem. Don’t be surprised to find some peaks greater than 6 dB above average. Think of it like a lot of speakers playing simultaneously, with some playing 10 times louder than your speakers when playing at moderately loud levels. Every room is different and every speaker produces different radiation patterns.

Geoff is right. Have you ever set up your speakers outside? They sound excellent, but just have no volume, or bass. That is what the room provides. It's way more than most people think.

Conversely, I HATE music played and heard outside. My drumset sounds thin, flat, and dead, with no resonance, no low frequency fullness, no sustain. Music reproduction is a different matter, added room resonance, fullness, and sustain (all boom) very undesirable.