Where to start with room acoustics

The obvious first steps are:

- speaker placement & listening position: you should learn about bass reinforcement and how the position of the speakers and listening chair can null or reinforce certain frequencies. There are several web sites with Java programs to visualize this for you. Just search. Also, be very "true" with the distance from each speaker to your chair, also make sure any toe in is the same for both sides. Use a ruler and be precise.

- 1st reflection points: use the old mirror trick to dampen 1st reflection points on the side walls. The room may also benefit from looking at secondary points as well, like windows, floors, ceiling. Just don't overdo it. An overly dead room is just as bad as an overly lively one.

These 2 simple things should fill your time nicely. If things don't sound right to you after this, then I would suggest investigating other options. These 2 are (mostly) free and just take time.

Enjoy,
Bob

Great thread, 2 questions:
PTM, can you expand on the "old mirror trick"? I can guess what you mean, but I am not familiar.
Warnerwh, another simple question; when people speak of the LEDE method, which end is live and which is dead? Also, is treating the wall behind your speakers only effective for management of low frequencies?
Thanks, Jb3

Have someone take a mirror and slide it along the wall. When you see the speaker in the mirror with you sitting in your listening position, that is the first reflection point for that speaker in your seating position. Repeat the procedure for each speaker. Place absorption at these points. If you want the room to sound more spaceous, try some diffusors at the back of the room. I've found that understanding the proper place to put your chair is crucial. If you go to www.guidetohometheater.com there is a sweet spot calculator that will tell you what your room modes are. Also, experiment with speaker placement. The closeness to the wall has a dramtic effect on bass response as you likely know. Lastly,you will need some sort of test cd and and sound meter to give you an idea of what is actually going on in your room. Every room is different. The type of carpet and pad, how much furniture is in the room, and type of window treatments. Don't rush the process. Start with the first reflection point as that's one universal requirement. Experiment with the other treatments. You'll likely need bass traps but how many will depend on the other factors.

Don't fear that you have to buy lots of truly ugly hardware to properly dampen a room, either. My 14x24-30x8 with lots of openings still sounds quite properly "dead" because of wall-to-wall, stuffed sofa (L) and big chair (R), each topped with a propped pillow at the reflection points AT WILL if the recording demands it! Cross-beamed ceilings break up these reflections well, but the biggest factor is that I sit in a smallish 7.5' nearfield triangle 8' out from the front (back...you know) wall, creating a stage with phenomenal depth precision, despite the 7' Steinway back there. Learning to pull my listening chair forward one extra foot closer (it sits in a double-doorway to a 6x10 library behind it), was the only tweak that room-mode analysis provided. I was doing that anyway when I noticed that if I leaned forward a lot the stage blossomed perfectly. Starting with a smallish nearfield triangle in a deadened room certainly works, as the first-arrivals predominate, and you get a good feel for your speakers. You can then widen and lengthen the triangle as the room boundaries, aethetics and preference combine. Lots of folks start at the 1/3 points, too. Damping sidewalls just right obviously has a great effect, but the bigger surprise for me was the huge stage depth provided by having 8' behind the speaker plane for trios and quartets to inhabit. I often "see" pianists sitting AT MY PIANO, with the standup on one side, cymbals on the other. On great orchestral/choral stuff it seems the front bushes and yard are the stage! So don't feel you have to really sweat this out and use the WHOLE room's geometry at first, getting all the modes nulled and all surfaces treated. Start small, then spread out, tweaking as the triangle grows.... Worked for me. Have fun.

LEDE is treated on the side of the system leaving the rest of the room live. Very common among very knowledgeable people as in recording studios or the best audio setups. There's lots of information on it. As far as bass is concerned the largest problem is of course corners but tube traps are necessary to tame bass, foam alone won't do it. The traps may be set in different areas of the room depending of course on your room. Check out Jon Risch's DIY site. Lots of good info there including how to make your own bass traps for alot less money and they work great. Good luck. You'll be glad you treated your room. Unless it is a very dead room I'd try some treatment behind the system.