A few not-so-obvious things I learned doing room treatment
I'm close to the end of my room treatment process (going on 8 months). Some folks here have been kind enough to share advice and reactions with me as I told you about my weird, low-ceilinged basement listening space and my attempt to learn how to make it sound better.
While many here know these lessons already and will want to skip this post, I'll share a few things I've learned that may be of more general value to others beginning this process. I'm focusing on what is NOT part of every beginner's lesson from a thousand books and websites (such as: get your speakers away from the wall, look for first reflection points, put down a rug, etc.).
1. Measurement is indispensable. I should have made very careful measurements of dimensions right at the get go. Room size, speaker dimensions and distance of various drivers to floor, etc.
2. REW or some kind of software & mic is indispensable as one tool. I read a lot of posts which said, "Just use your ears — they're enough." That, I found, is patently false. The reality checks and more specific information I got from REW — about ringing, about boomy spots, about smearing of image — helped me place absorbers and diffusors much more accurately and stopped me from trying to guess my way to that needle inside the haystack.
3. Making prototype panels helped a lot and was easy and inexpensive. I bought 6 OC 703 panels and my wife made a "pillowcase" with some durable fabric around them. No wooden frames. Two 2" panels, wrapped, went easily on the ceiling and the other four panels became two 4" panels. These gave me a lot of combinations to try out for absorption at different frequencies and for taming some aggressive impulses.
4. Real Traps Mondo traps are better, for the most part, for my bass issues. I had the good fortune to have someone give me a bunch of traps he was not using any longer — GIK bass traps, GIK Corner traps, GIK Q diffusers, and ATS absorbers and small 2' bass traps. 14 in all. Of all of these, for bass absorption, the Real Traps were much more effective. I have heard the GIK soffit trap is excellent, too, but I have not tried it. In the end, I used everything I have, but I could probably save space with more Real Traps.
5. Stuffing old pillows with R38. I had some OC R38 on hand and hung it in a couple of closets to try to add dampening there. Not that effective. But I had a couple old couch cushions which were not being used — I took out their batting and stuffed as much R38 in there as the zipper could contain — and wow! R38, compressed into a cushion was much more powerful than several of the larger nice looking GIK or ATS traps. And, they're remarkably easy to place and move, even behind things. Just have to keep measuring to see what moves the needle in REW.
6. The room IS half. This one is not a hack and it's a truism mentioned repeatedly. But I dealt with my room after all of my speaker and gear tryouts, all while making judgments about this or that speaker being too bright or boomy or whatever. Now, I realize that without having my room under control, those were all just guesses. Who knows, maybe I would have kept those Martin Logans if I had figured out how to control first reflection points and bass boom? At any rate, so much of my time went into reading and assessing gear as it sounded in my untreated room and I realize now that the value of those judgments was about half of what I thought it was. I learned something by comparing them in the same (untreated) room, but now I am really set up to hear things. This is an inconvenient truth, insofar as it takes any number of debates and analyses about gear and makes them so much less "serious" because of this unacknowledged X factor.