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. 


128x128hilde45
Very good advice. I accidentally bought a house with outstanding acoustics. I have been shocked at how important they are even after decades fiddling with ribbon speakers... half the sound quality... I have to agree.
I know that acoustic controls are the key to audio experience more than the choice of gear itself...

It is a very important information for newcomers then i concur with it also....I must say that this was not so obvious at all to me also before experiencing it... Then a good thread....
Hilde45,

Thanks so much for this thread.  After futzing with my room acoustics/set up endlessly over the last few years, I recently made changes that so-improved SQ, I decided the room would be fully addressed—either by ear or based on REW measurements—so that I may actually hear my current audio system with the veil of poor acoustics removed—fully, or nearly so. Only then does it make sense to evaluate new gear or ancillaries, as you report. 

But, since my room does sound really good and I think is pretty sorted out, I was very much debating on whether to continue by ear or by REW.  There is a rather short list of rational next steps I’d try that every audiophile knows: treatment on front walls, ceiling—for example.  Even having a company like GIK or real-traps recommend a treatment plan for my room didn’t seem ideal.  My hunch has been that REW is needed.  And your findings seal it.

I have found an extremely knowledgeable person to read my room using REW, explain the results to me and advise on treatments or changes in set up based on them.  The person charges for his services so it is important to make sure his service will provide data that is actionable by “interviewing” him before committing.  Your OP help in that regrade.

All your reviews of branded and DIY treatments are useful too.

Any tips on which microphone to buy?  I will be borrowing a friend’s Mac Book to run REW.


Should add that while I “think” my room is pretty sorted out based on how much better I’ve made it sound over time....it will be very interesting to see what REW says about my “sorting”.  Lol.
https://www.minidsp.com/products/acoustic-measurement/umik-1 should be sufficient. 

I will be interested how the person you hired will help you. There are videos about how to use the software online that will give you some background and it might be nice for you to know something before this person comes over so you and he or she can get right to work. I'm really glad that the thread helped you.

In my experience what the software will provide will be the other side of a dialectical process where you will measure and see where there are either peaks or big valleys in the graph response and then you will move your speakers and / or your listening position in order to see what changes. After you have made some adjustments that seem to improve on some aspect of the graph, you will go and sit and listen to see if you can hear what the new readings show. In other words you will begin to establish a correspondence in your mind between your sensation / listening experience and what the graph is telling you. As I said, this is a dialectical and iterative process and it will be very rewarding and you will be able to do much of it without the expert help.