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DIY Acoustic Treatment Master Thread

post #1 of 109
Thread Starter 
So with all the horn craze and added speaker builds here lately I thought we should all get our rooms sounding good. Pointless to have great sounding speakers if they are playing in a bad room. So here is what I am thinking, we try and put together a variety of different acoustic treatments that we make for ourselves, get a parts list for each type, and a cost breakdown. A full how to that includes diffusers, absorbers, bass traps, and any other types we can think of.


I got the idea of doing this thread after being frustrated trying to read through the master acoustics thread that has over 5000 posts and no index. Once we get this thread with some content I will start up a good index.
post #2 of 109
Two words: DO IT!

The living room in my old apartment had a vicious echo. The easiest way to test this in your room is the 'clap test'. Just clap your hands as hard as you can and listen for the echo. If you hear an echo, your room will benefit from room treatments. My old room echoed for nearly a second! Echos you hear clapping near the sound source are worse than those elsewhere in the room--since those are the ones your speakers will be dealing with.

My treatments are rectangles built from pine 1x4's, stuffed with R-30 insulation, covered with batting, and finally wrapped in burlap. I usually place 2 behind the fronts, and two more behind the listening position. This does an excellent job of knocking out the echo from the fronts. Other excellent spots are wherever you're getting a direct reflection from your speakers to the listening position--on the floor, the ceiling, and the walls between you and the speakers are all sources of echo.

All in all, I was out all of $120 for everything, including a new staple gun and hand saw (all the tools you'll need, outside of a heavy knife and scissors). The difference was remarkable--voices that were muddied, cleared. Instruments that were 'somewhere', materialized in front of me. So do it. You'll thank yourself if you do.

I'd be glad to go into more detail if you'd like.

I can go more into depth if you'd like me to.
post #3 of 109
Subscribed.. Cant wait to see some ideas from everyone!
post #4 of 109
He's a DIY side surround next to some of my Diffusors. Not sure how safe the blue styrofoam is but the diffusors work great.

The room is live in back and dead up front. Really makes a difference. I use 2" ridgid OC 703 board. Rumor has it 4" hits a wider spectrum of sound.
post #5 of 109
built 2 of these for my open living room so far! hope they work well. and baaahhhh to my floor, it is not level at certain places., going to build up to 10 more of these to go around my room.

first time building these, 2x 2" oc703 per frame. birch plywood - homedepot crap grade, birch that looked perfectly flat, but wasn't. ripped to size on a table saw and miter saw i have never used before.
burlap adhered to the sides of the oc703 with scotch 90 spray adhesive. No adhesive on the faces that are not covered with wood. friction fit in the frame. approximately $35 in materials each, maybe less. will maybe shellac them eventually.
post #6 of 109
post #7 of 109
Here is a pic of one of my sidewall DIY Poly Diffusor arrays (along with a bunch of broadband absorbers placed at primary and secondary reflection points lower on the sidewalls). The build thread for this project is found on a Canadian AV site I frequent.




Next is a couple of pics of my DIY Skyline Diffusor project, one "naked" and the others finished and in place. Again the associated build thread is located on the CAM Forums.








The 2'x4'x4" broadband absorber panels seen in the first pic are DIY also but built before it occurred to me that others might find a diary of their construction useful. I've built Fiberglass pipe insulation "Tube Traps" too but again there is no build diary. There is however, a ridiculously long thread (you've been forewarned! ) with lots of pics which recounts the evolution of my dedicated room, the gear within, and the room acoustic treatments used to eek the best performance possible.

Happy Trails!
Vince@Freewheelcycle.com
post #8 of 109
Great idea for a thread.

It should prove very beneficial when an index is added and perhaps a sticky thread.

I am exploring the idea of treatments myself.
post #9 of 109
Quote:
Originally Posted by kgveteran View Post

He's a DIY side surround next to some of my Diffusors. Not sure how safe the blue styrofoam is but the diffusors work great.

The room is live in back and dead up front. Really makes a difference. I use 2" ridgid OC 703 board. Rumor has it 4" hits a wider spectrum of sound.

Blue styrofoam should never be used in an exposed application. It it flammable and creates toxic smoke. Not sure how you could treat/coat it for safety.
post #10 of 109
Here is an old picture of my front wall with the screen removed. Panel frames are 25.5" x 49.5" x 3" deep. Inside of frame is 24" x 48" to use a full piece (no waste) of semi-ridged mineral wool. I have 2" of mineral wool in each, covered with AT fabric. This gives a 1" air space behind the mineral wool. Corner traps are made similar except I used 4" thick mineral wool. Back wall is treated the same. Blocking above the panels is what holds the screen out from the wall. The shaft below the blocking is part of my masking system.
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Wall has been changed to this:
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Now using JTR T8 behind AT screen.
post #11 of 109
this is a good thread and going to be a tough one, as different speaker designs match with different acoustic treatments.

i'll kick in:

gik
http://www.gikacoustics.com/

ready acoustics
http://www.readyacoustics.com/index.php

the guys at the bbc (britian) have also experimented with several designs. they had a pretty good paper, but i can't find it at the moment.
post #12 of 109
There is lots of good info in my old room treatment thread:

http://www.avsforum.com/avs-vb/showt...&highlight=faq

DIY speakers is really the wrong forum for this type of thread, but I'll be reading every post of it.

Btw, I went with the 2" Owens Corning stuff and it made a very noticeable difference in my sound. I'd do it again in a heartbeat, but I'd use 1" instead. The 2" stuff sticks out like a sore thumb on my walls.
I should mention that I have bare flooring (not carpeting).
post #13 of 109
almost forgot about boundary layer cancellation, though i don't have a link this is one of the most effective methods for fixing bass modes.

another random bit: green glue. http://www.greengluecompany.com/

ethan weiner's basstraps site should also be included. i don't have a link.
post #14 of 109
"DIY speakers is really the wrong forum for this type of thread,"

with respect, i disagree. lots of room treatments are diy and diy speaker seems to be the most 'scientific/techy' area of the whole avs website. i think this is why he posted here.
post #15 of 109
Quote:
Originally Posted by LTD02 View Post

"DIY speakers is really the wrong forum for this type of thread,"

with respect, i disagree. lots of room treatments are diy and diy speaker seems to be the most 'scientific/techy' area of the whole avs website. i think this is why he posted here.

I agree. If you are willing to build large subs and or build your own speakers, then you certainly would be the type to build sound treatments. I go to the speaker threads and see expensive speakers in rooms that have terrible acoustics.
post #16 of 109
here is the bbc paper:

The Design of a Modular Sound Absorber for Very Low Frequencies
http://downloads.bbc.co.uk/rd/pubs/reports/1992-10.pdf
post #17 of 109
ethan weiner links:

diy side:
http://www.ethanwiner.com/basstrap.html

commercial side:
http://www.realtraps.com/
post #18 of 109
Here's how I made my broadband absorbers:

www.basstraps.net/DIY-BASS-TRAPS-MADE-EASY.pdf

I have 10 4" thick ones for bass trapping, 4 2" ones for first reflections...

They make a serious difference.

JSS
post #19 of 109
Quote:
Originally Posted by maxmercy View Post

Here's how I made my broadband absorbers:

www.basstraps.net/DIY-BASS-TRAPS-MADE-EASY.pdf

I have 10 4" thick ones for bass trapping, 4 2" ones for first reflections...

They make a serious difference.

Nice PDF! Well documented and easy to follow, I like it!
post #20 of 109
Thread Starter 
All VERY good examples so far. Building some standard panels for 1st order reflection points is probably going to be my next project. My room is pretty big with a lot of bare walls. I can tell from listening in smaller rooms that my setup should sound better and I believe that some panels will probably help out. I'm not quite ready for big bass traps yet, but I figure a couple on the wall will help out and make the room sound much better. Looking around the internet at others that have done this I believe for as cheaply as $75-100 you can make 4-2'x4' panels. Compared to what companies charge that is a very good deal.

UFOKillerz, That's a good idea about the moveable panels. I believe if someone has a closet to put them in then they may be able to get those past the wife a little easier. It may be easier to move them to the spot you need on occasion than to try and say, "Hey honey, I want to put up some acoustic panels...on the walls".

On a side note and unrelated, is anyone having trouble getting e-mail notifications for your subscribed threads? I haven't got a single one for this one or the Danley thread and that has had probably 30 posts since my last notification. EDIT...WTF?? I just looked at my subscriptions and it went up from around 15 or 20 to 123!!! What's going on there? Did they make a update for the forum that makes it sort of like HTShack so that if you post then it auto-subscribes you??
post #21 of 109
Thread Starter 
http://www.realtraps.com/art_room-setup.htm

There's a decent tutorial page as to how to set them up in the first place.

post #22 of 109
If you are near any of these locations, SPI has the absolute best pricing on OC703 or equivalent rigid fiberglass. It is much much cheaper than anything you could find online.

http://www.spi-co.com/directory.html

Look here for absorption coefficients

http://www.bobgolds.com/AbsorptionCoefficients.htm

If you will be making the big Superchunk corner bass absorbers, make sure you buy an electric knife for a few bucks at Walmart--makes cutting that stuff a breeze.
post #23 of 109
If people are going to make their own I suggest trying their best to find a local dealer. I made the ones below and the total cost was around 500 bucks and I still have about 17 sheets of 703 left over (that was for the 703, wood, staples and fabric).

If you by the 703 online you will be paying at least 75 bucks for only 6 sheets of 703.

What I ended up making was 2 2” panels, 2 4” panels, 2 8’ bass traps and one little guy that is velcroed to the end table near the speaker (these pictures show all my old gear).

Also, for the ones that would straddle corners, I cut the frame at an angle so they would sit flush against the wall.




















James
post #24 of 109
One of the best .pdf files I have ever found....this was the impetus to my opening of Pandora's Box, and the hell you will go through once you decide to measure things...you have been warned...

http://accucalhd.com/documents/audio...%20Theater.pdf

JSS
post #25 of 109
Quote:
Originally Posted by maxmercy View Post

Here's how I made my broadband absorbers:

www.basstraps.net/DIY-BASS-TRAPS-MADE-EASY.pdf

I have 10 4" thick ones for bass trapping, 4 2" ones for first reflections...

They make a serious difference.

JSS

I have a small room, so reflections can be a big problem. I went with sixteen 2" panels and four 4" panels (bass traps). The frames hold the panels away from the walls.
post #26 of 109
Interesting and useful information, tools, and links can be found here...Small Room Acoustics
post #27 of 109
Here's something I did one time that was very effective. If you want to experiment, it's pretty easy to do. Afterwards, you can add the fiberglass to your attic, or figure out how to hide or make it look acceptable.

In two room corners near the speakers, I tacked up a piece of standard 3.5" fiberglass with the kraft paper side out, from floor to ceiling leaving a small airspace. It made a huge difference in the midbass / midrange. I had planned to make a cover later, but never did, so I later took it down. If your room is big, try taping two thicker pieces together to form a larger airspace in the corner. It will tend to be round not flat, and will aid dispersion as well as absorbtion.

What I thought would work, but haven't tried is similar. Using the same 3.5" fiberglass, tape several pieces together with duct tape on the paper, and form it into a big tube about 15" to 30" in diameter, leaving just an airspace in the middle. Seal the ends with wood, or more fiberglass and tape.
post #28 of 109
Quote:
Originally Posted by Fatawan View Post

If you are near any of these locations, SPI has the absolute best pricing on OC703 or equivalent rigid fiberglass. It is much much cheaper than anything you could find online.

http://www.spi-co.com/directory.html

Look here for absorption coefficients

http://www.bobgolds.com/AbsorptionCoefficients.htm

If you will be making the big Superchunk corner bass absorbers, make sure you buy an electric knife for a few bucks at Walmart--makes cutting that stuff a breeze.

Great thread! This is exactly the info I've been looking for. I've also been searching for a couple weeks for a local OC 703 dealer with no luck. Just called SPI and they have it. Only about $10 cheaper in cost but saves me $20-$40 in shipping.

Now I have to work on info for moveable diffusor stands.

Thanks

Stopped by SPI today and picked up 12 24"x48" panels of 2" OC703. Saved me about $80 which I can put toward the diffussors.
post #29 of 109
Here is a link to a build thread I had going a few months back.

There are plenty of pictures on how I did this. My panels are left "unfinished" for most but I like the way they look.

I hope this helps:

http://www.avsforum.com/avs-vb/showthread.php?t=1183930
post #30 of 109
Use a table saw to make a bevel on the front edge of the boards for your frame. I used AT fabric from Frabricmate. http://www.fabricmate.com/audiomesh.php Nice choice of colors and the fabric looks good. Should be able to make nice enough panels that are WAF approved. These are the same panels that I have in the back of my dedicated room. On a light gray wall they look pretty dark. On a black wall they almost look white.
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