Posted by Winston Smith (A) on June 07, 2012 at 16:56:30

Dear Ethan-

I will be using your “Deep-Bass” and “Upper-Bass” DIY wall trap designs in the Music Room I am currently building. Thanks so much!! But I need some guidance, please.

FYI- The room will have a wooden (stained spruce) ceiling 14’ high, that begins sloping upwards from the front wall at 8.5’, then flattens out in the middle at 14’ for about 30”, then slopes downward behind the listener to the rear wall intersecting therewith again at 8.5’. The room is 32’ long by 21’ wide, with drywall on all the sides, and heavy carpet on the floor. Four minimal windows (48”w x 24”h), two on each of the side walls, which will be covered by acoustically deadening draperies.

My questions are these:

1.) In New Zealand, the closest thing they have to the 24” x 96” x 1” rigid fiberglass is sized 94” x 47” x 1” (2400mm x 1200mm x 25mm), which is standard size here. My builder says it would be less costly to simply use this size (double the width of your trap designs.) I told him I would ask you if this is no problem. I was concerned the extra width might change the frequency response of the “Upper-Bass” and “Deep-Bass” traps substantially, but maybe not. What is your opinion? Can I use the NZ standard size with no loss in performance?

2.) I would like to install about 20 of the Upper Bass and Deep Bass wall-mounted traps on the various walls of the Music Room (or ten, if the double-width standard sizing here in NZ is no problem.) However, I am having a hard time finding Owens-Corning (or similar type) 1” rigid fiberglass insulation panels here in New Zealand. For some reason they seem to have mostly thick/fluffy standard-type wall/ceiling fiberglass insulation or semi-rigid pipe-wrapping fiberglass available, but not the rigid fiberglass. What standard do I need to meet to have the same effect as the 1” rigid fiberglass panels you recommend? What substitutes could I employ instead of the rigid fiberglass that would provide the same effect?

3.) I already have six large (4’ x 8’ x 3”) Sonex-type acoustical panels that I was simply going to place directly on top of the Music Room’s side-wall mounted Deep and Upper Bass traps, to create full-range traps to capture the first reflections. I just figured it would be simpler and less costly to completely cover these Upper/Deep Bass traps with the Sonex to get full-range absorption on the side walls, rather than build separate mid/treble traps that would need to be fit alongside the Upper/Deep Bass traps. Do you see any problems with this plan? (The front wall facing the listener would get covered in equal amounts of the standard Upper and Deep Bass traps, with no Sonex on them at all, so as not to suck out all the mids and the highs, BTW.)

4.) Regarding DIY corner traps, I had planned to have my builder diagonally cover the corners with airtight-sealed drywall from floor to ceiling (about 30” wide, 8.5’ tall), putting unopened rolls of fiberglass insulation stacked vertically behind it for DIY corner traps. Good idea? If so, what R-value for the insulation rolls should I use for best results, i.e., can I go low to save cost, or is higher better? (This approach was inspired by Jon Risch’s super-cheap, super-easy “Quick and Dirty” corner bass traps idea, BTW. I figured the sealed drywall across each corner very gently compressing and covering the rolls of insulation might work well, and DEFINITELY will improve the wife acceptance factor enormously!)

Thank you in advance for any help you can offer in these regards, Ethan. Again, I simply cannot express my gratitude to you for your providing audiophiles such wonderful DIY tools and your invaluable assistance in helping us to achieve our listening goals and dreams.

Cheers!

WS