For the past two weeks I've been obsessed over my listening room's acoustics. I'm sure that acoustic problems are now invading the space (or I've read too much about the subject and I'm just noticing them now, always train your ears). The most obvious problem is too wide a stereo image. For example, I'll get a tight, centered combo of snare and kick drum that I can imagine a drummer playing and then he hits a cymbal eight feet away over past the right speaker. Another problem is losing center imaged singers to a weird lobing split between either speaker—the voice may suddenly collapse to one side. These anomalies are subtle, don't think my room is crap.
I need acoustic treatments and I don't want to spend much money. Enter Jon Risch's (of Audio Asylum Tweak/DIY moderator fame) DIY Acoustic Panels (a simple wood frame covered with burlap and stuffed with fiberglass insulation). The advantage of these panels is their wide frequency bandwidth absorption, sucking up high and medium frequencies and even upper bass down to 100 Hz. Other acoustic treatments with a narrower bandwidth only deaden higher frequencies and let the bass remain bloated. Plus they're more expensive and usually have a low WAF (wife acceptance factor).
After measuring the room's width, height and length and the distances between my loudspeakers, the walls and me, I've entered all the values into room acoustic spreadsheets and drawn a floorplan in Omnigraffle (see pic below, the angled lines between my head and the loudspeakers are the ones to pay attention to). The spreadsheet just told me I have lots of nulls and peaks and frequencies that are too close. I overlaid first reflection points on the floorplan to figure where I could use some acoustic absorption panels.
I need at least four 17"x48" Jon Risch DIY acoustic panels to cover my side wall first reflection points (the putty colored rectangles along the walls in the diagram above). I have to make the panels at half their normal width because of the large armchairs along the sidewalls between me and my Vandersteen 1c's. If these first panels help, I'll add two more on the back wall, negotiating around the projection screen. Now, where do I buy all the materials?
I wish sourcing parts for audiophile DIY projects was as easy as dropping by the grocery store for chocolate chip cookie ingredients. To get all the materials for Jon Risch's DIY acoustic panels I have to visit up to two hardware super stores (make that one Home Depot was a bust) and a fabric store in two different towns. Is any money I'm saving with DIY just being blown on gas and new tools I have to buy?
Why can't one store carry the following for my six panels?
- 30 ft. of R-25 8 in thick, 15 in. wide fiberglass insulation
- 12 x 4 ft. long 1×4 boards
- 12 x 15 in. 1×4 boards that I have to cut to size myself (or have the hardware store do it depending on the fee)
- 10 yds. of 100% polyester batting
- 10 yds. of Burlap fabric in a color my wife will accept
- Eye-hooks and chains to hang the contraptions to the ceiling for easy install and removal
- Tools: 2.5 in. No. 8 Self tapping screws, squaring vise
So after trekking all over the suburbs for lumber, tools and craft fabric, I'll finally have all the materials in front of me and be ready to build. I'll try to take pictures and write a proper how-to followed by a A/B listening test for music and movies.
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