Have you been yelled at for watching your latest Superbit DVD "too loud" by your mom / dad / child / spouse / neighbor? Tired of having the Tiki-bar TV guys next door in the background of your podcast recording session? In today's how-to we cover tricks to improve your room acoustics for better listening or recording pleasure. Yeah, we know it may seem a little esoteric -- and our own Engadget Podcast could probably take a hint here -- but you'd be surprised at how nice some peace n' quiet actually is.
Treating a room to improve its acoustic properties is a combination of art and science, especially for the home acoustic engineer on a budget. With an unlimited budget, a room can be double walled and covered in commercial acoustic paneling. When trying to improve the acoustics of an existing room, whether for listening pleasure or anger prevention, a smaller budget is more of a challenge.
Every room has different challenges, but if you're building your podcasting studio or improving your home theater the same problems need to be solved. Sound transmission into and from the room needs to be reduced and the room's acoustics are probably less than ideal.
'Acoustic isolation' is trying to reduce sound transmission out of the room. Improving internal acoustics is a matter of reducing sound reverberation. Completely eliminating reverb is not always desired. Even with today's sound processing technology, concert halls are still designed to use natural reverberation to improve sound for live performances.
For today's how-to we're making treatments for an unfinished basement. Finishing out the basement isn't an option at this house, so everything we do needs to be removable when we move out. Our home theater area has a concrete floor, two concrete walls, and two 'walls' that are open. Every surface needs some sort of acoustic treatment.
Often the simplest solution is one of the best. To keep excessive sound from going upstairs, we hung acoustic ceiling tile on the floor studs. Ceiling tile is easy to get and has acoustic ratings. Basic ceiling tile is pretty inexpensive. For about $60 in ceiling tile, we covered the entire ceiling of our home theater area. Rather than hang the tile with a drop frame, we screwed it directly to the floor joists. When we move out, a quick session with the cordless drill will take these down. The tile is pretty fragile, so using washers on the screw heads is advised. For the floor, a thick wool rug makes a great sound damper.
There are plenty of commercial products for sound treatment. Our temporary install is on a budget, so we built some simple portable acoustic panels to help reduce sound transmission and reverb.
To make your own, you'll need the following:
- 3-1/2 inch thick 15 inch wide rolled fiberglass insulation
- Polyester batting
- 1-inch by 3-inch pine boards
- 4-foot by 8-foot 3/16-inch lauan or plywood board
- Liquid nails adhesive
- Tools: saw, hammer, sharp scissors, staple gun.
Dow Corning R-13 insulation runs about $10 a roll. It's made to go between wall studs, so it's 15 inches wide. One roll should be enough to make eight to ten panels.
To make five panels, we need ten 48-inch 1x3s, and ten 15-inch 1x3 pieces for a total of seven 8-foot 1x3-inch boards. It's important to get boards that aren't warped. These boards are pretty thin, so it will be fairly annoying but worth the effort. Look down each board from the end to see how warped the board is.
To keep it light and inexpensive, we used lauan plywood made for floor backing. These panels have a smooth finish and are cheap. A four foot by eight foot panel runs about $10.
Just about every hardware store that sells lumber has a panel saw. Save yourself some pain and have them slice the four by eight lauan into 48 inch by 16.5-inch pieces. Most stores don't guarantee their measurements, so keep an eye on them to make sure they get them close enough. Luckily, the cuts don't have to be perfect.
We picked up this not so stylish green fabric off the wally world clearance shelf for $1 a yard.
We cut our 1x3s down using our handy miter saw. Ten 15 inch cuts for then ends and ten 48 inch cuts for the sides.
Nailing the frames together goes quickly. Start with one side, then locate the other side using the 15-inch end pieces to get the spacing correct. Then add the ends last. Finally a couple nails at each corner help connect it all. Wood glue is optional.
Lay the fiberglass out over the frame and cut it to fit. We tried a utility knife first, but scissors worked best. A bit of liquid nails adhesive under each end will keep the fiberglass in position.
We laid out polyester batting over the frame, and cut it with excess to cover the edges of the panels.
We wrapped the whole thing in fabric and stapled the edges. A quick trim and the panel is completed.
To hang our panels, we used some cheap brass hooks at the topmost corners of the panel. These won't take much abuse, but they'll do the job.
Our row of sound panels hung up in the basement. We're still playing around with the spacing, but they definitely improved the acoustics in the room. If you're not into hanging them, add some hinges and you can make a nifty sound barrier disguised as a changing screen.