I record, produce and mix indie music under the name Language Please. Since arriving home from college a few weeks ago, I've decided to rearrange my childhood bedroom so that it's more suitable for mixing. I've really enjoyed reading these forums and learning about acoustic treatment.
However, even after rearranging my room so that my speakers fire down the long axis, and building and hanging my own bass traps, I am facing an ungodly bass resonance around 140hz when I do a sine sweep. My room is an unusual shape with measurements of 14.5ft x 13.5ft x 7.5ft (with the vertical wall before the slant at 56" tall).
I've hung 6 inch bass traps on the front and back wall/ceiling corner where I can, and have a corner trap on the front left corner (the front right has a bookshelf).
This bass resonance is strongest right at the listening position of my desk, with noticeable buildup behind the speakers. Pulling the desk farther away from the wall doesn't seem to help. Before rearranging the room, my desk was under one of the slants in the corner firing down the short axis of the room. I didn't have this bass frequency problem when the desk was positioned there (however other things do sound better in the current arrangement).
I have a few more bass traps I'm waiting to hang (thought I would ask you all first). The 4 I have installed have maybe made a difference but the resonance still makes even music listening very unpleasant. Any idea what I could do to effectively combat this?
Let me know what other information I can provide about my case.
I can tell you that 140Hz is related to an 8' or 16' boundary. You can try treating that parallel dimension more then take a measurement to see whether it helped.
EDIT: I can see that you installed four absorbers - some of which are relatively small. Ethan will tell you that coverage is more important than thickness, i.e., six-inch-thick panels are great if you have more of your surfaces covered by them. By way of comparison, I have 20 4" panels and I'll probably double that number before long.
If you can, make 20 more 2'x4'x6" panels and install them. From there, we can talk about optimizing placement.
Amazing, thanks Hexspa. I have 3 more 2'x4'x6" panels I've already made, and I'm trying to decide where to place them. When you say 140hz is related to the 8' boundary, what does that mean? My ceiling is about 8ft tall. Does this mean I should treat my ceiling?
But here's the thing: don't waste your precious few panels treating a bass resonance. Use them to create a reflection-free-zone. That's going to give you maximum bang-for-buck: clarity and improved stereo image where your hearing is sensitive. Relatively, it takes few panels to create a RFZ yet the return is high. 4" is what I consider minimum for music but you can do 6" or 8" too. Once you get that set up, you can add more panels until your final days and still wonder, "What if I add one here..?"