Most "mild" room treatments utilizing thin layers of foam and / or "stuffed" cloth materials, etc... are actually very non-linear in their absorption of frequencies. I commented on this many, many years ago in the Agon archives and posted links to actual absorption curves for commonly used devices. I did this after someone inquired about purchasing some of these devices and told them that they would actually be creating more of a problem. In plain English, most of those types of devices are a big mess.
If you want to treat a room and end up with results that are actually better / more linear than what you started with, rather than just shifting problem areas to different frequency regions, you have to treat the room as a whole. Once again, i recommend that folks pick up and read some books by F. Alton Everest BEFORE spending money on products that you can do a better job of buildng yourself and impliment them in a manner that is more suitable to obtaining optimum results. Not all rooms are the same, nor do they require the same type and quantity of treatments. If they did, they could design speakers that worked within those constraints and did so perfectly. Sean
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