How do I dampen my listening environment?

Please, come on. It needs to be just big enough to see some of the speaker you're working on.

I moved the stereo into a larger room in my home, and along the way, pulled up the carpet, installed a maple hardwood floor, and worried about the same kind of issue. The acoustics were hard, and the last thing I needed was bright, harsh sound. As I walked around, clapping my hands and yelling out, some major sweating over what would come sonically ensued.

Thankfully, the end result is very, very good. In fact, friends would listen to the same system, comment on the sound, and ask what upgrades I'd made at the same time. Only one, the room.

What I did had no planning in regards to the system, just the typical things one would put in a room. As things ended up, I needed no audio related room treatments. As has been mentioned, curtains were the first thing I did. While my curtains are fairly heavy, they aren't anything special. However, I also have a more sheer, gauzy type inside the curtains that show in the room. The combination of both likely takes care of the hard glass surface of the windows. Next, a nice, fairly thick (again, nothing out of the ordinary), wool rug. Mine is about 8' X 11', and I would advise one not to skimp on the size. In addition to providing seating, comfortable furniture did a lot more than I would have expected in helping out the acoustics. Some "unintended" room treatments, such as things to brighten up the room like plants, lamps with large shades, etc. played a role. Finally, flexibility in terms of loudspeaker positioning in the room will always make a major difference, and is likely the one parameter most people are hamstrung by. Thankfully, I had (mostly) total freedom there.

Again, what I feared being horrible, softened up nicely once the room was furnished. Once I hooked everything up, I was more than pleasantly surprised with how things came together.

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

Acoustat

I may have this wrong, but from what I have read there are only four reflection points on the side walls that matter in a two speaker setup. The reason is that each speaker has only one reflection point on each side wall that directs sound to the listening position. All the other reflections off the side walls pass either in front of or behind the listening position. The mirror technique for locating these reflection points works because a mirror on the side wall will reflect light coming from the speaker position to the listening position only when placed at the reflection point.

When I used a mirror to locate the side wall reflection points in my listening room, I used a mirror about 1 foot x 1 foot and the trial and error method. It was a PITA because I didn’t have any readily available furniture on which I could place the mirror at eye level when sitting in the listening position, and I had to improvise by stacking things. So, yes, a larger mirror would have made the whole process easier for me, but a larger mirror wasn’t necessary to determine 3rd, 4th and other reflection points. The easiest way to use the mirror to locate the reflection points is to have another person hold the mirror and move it around until the person sitting in the listening position can see the light from the speaker reflected.

Other reflections in the room can cause excessive reverberation or ringing, 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.

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?