How do I dampen my listening environment?

I said "It should be the same size as you wall. Otherwise how would you know what is missing?"

If the first reflection point is the only point of reflections you are worried about then sure one small mirror will do. But the first reflection is only a small fraction of the reflections we hear. Dont forget to put mirrors on the front wall, rear wall, ceiling and floor! They may be 2nd, 3rd 4th... reflection points but add up much more than one single reflection point.

Bob

Octave Doctor PHP

"12-22-09: Unsound
How big a mirror should one use?"

It should be the same size as you wall. Otherwise how would you know what is missing?

Bob

Dougmc said, "but this is different in nature from the problem caused by 1st and 2nd reflection points. Excessive reverberation causes smearing and overhang and muddies the sound. First and second reflection points create a time difference in a specific sound reaching the listener and makes it hard to determine the location of the sound within the soundstage. In other words, imaging of specific sound sources is impaired. The solution to both problems is absorption of the unwanted reflections. However, ringing (detected by clapping hands) is solved by distributing sufficient sound absorbing materials around the listening room. First and second reflection points are solved by having sound absorbing material at those specific points."

I agree 100%. What I was getting at is that 1st and 2nd reflection point are just the tip of the iceberg.
The initial post question was "How do I dampen a room?". The answer to that is you need more than the 1st and 2nd reflection points covered. Which is why you need a full room mirror including the ceiling and floor!

Bob
If the first one hundred db suck, why continue?