first diy diffuser build. QRD and 2D skyline types for Magnepan system.

Rclark · « **on:** 18 Apr 2013, 03:59 am »

http://www.amazon.com/Expanded-Polystyrene-Foam-Sheets-qty/dp/B0054R8Y20/ref=sr_1_2?ie=UTF8&qid=1366257345&sr=8-2&keywords=eps+foam

Maybe glue a couple back to back for 8" depth and use a QRD calculator and a saw?

Rob Babcock · « **Reply #1 on:** 18 Apr 2013, 04:15 am »

Wow, shipping is 2x the cost of the product!

I hope you have a local source. It seems that maybe that wouldn't be dense enough to do a lot at lower frequencies but I would think it would work for diffusion of higher frequencies.

Rclark · « **Reply #2 on:** 18 Apr 2013, 04:21 am »

Isn't that the stuff most diffusers are made from these days? I think it can handle as low as 3-500 hz if it's the same material.

medium jim · « **Reply #3 on:** 18 Apr 2013, 04:34 am »

Quote from: Rclark on 18 Apr 2013, 04:21 am

Isn't that the stuff most diffusers are made from these days? I think it can handle as low as 3-500 hz if it's the same material.

Try Lowes or Home Depot and you can even buy the materials to make the backing and trim to make them look pro.

You could also pick up a Ficus Tree or two which also work great.

Jim

jtwrace · « **Reply #4 on:** 18 Apr 2013, 07:59 am »

Quote from: Rclark on 18 Apr 2013, 03:59 am

http://www.amazon.com/Expanded-Polystyrene-Foam-Sheets-qty/dp/B0054R8Y20/ref=sr_1_2?ie=UTF8&qid=1366257345&sr=8-2&keywords=eps+foam

Maybe glue a couple back to back for 8" depth and use a QRD calculator and a saw?

Why bother? Just buy the proven diffusors from GIK or Real Traps and be done.

Most importantly, remember you must measure if you want it correct. Placing them in the room and not measuring is not going to yield the best result. It's science and you should treat it that way. Sadly, most people here will tell you what to do but have never done it themselves (and don't believe in it) and will give you a lot of misinformation.

It's so easy it sad that most fight it. I heard a great quote by an attorney today. "If you can't fight the Science, you fight the man" -J.J.

And that's exactly what goes on here.

Rclark · « **Reply #5 on:** 18 Apr 2013, 08:56 pm »

Well I may have found a local source. No Jason I'm fully on board with you there. It's just I'm getting ready to buy a motorcycle next month though so Dual Core (measure-er) will have to wait. Any large audio purchases are on hold for a few months and least I can do this cheaply and just fiddle with them.

PDR · « **Reply #6 on:** 18 Apr 2013, 09:47 pm »

Dont use glue, use foam in the can to glue them together.

As for the why bother part....well, you might enjoy it and even get some gratification
by building something with your own hands. For the $ involved you have very
little to loose.
Try a roofing or stucco supply house for your styro.

Rclark · « **Reply #7 on:** 18 Apr 2013, 09:53 pm »

They're gonna be pretty ugly, but I can at least get a feel. I'd like to build 7" depth, 3 of them at 2ft by 4 ft, for 8ft of coverage behind my Maggie's. I'm yonna see if I can't get this done on my next day off. It's gotta be local as shipping is ludicrous

Rclark · « **Reply #8 on:** 18 Apr 2013, 09:58 pm »

Home Depot's got 2" by 2ft by 4ft styro for $6.29 a sheet. I'm all over it.

medium jim · « **Reply #9 on:** 18 Apr 2013, 11:29 pm »

Quote from: Rclark on 18 Apr 2013, 09:58 pm

Home Depot's got 2" by 2ft by 4ft styro for $6.29 a sheet. I'm all over it.

Don't blame you. You might also think about sewing and craft stores, like Michaels (I believe they're nationwide) as they might come in different colors.

Nothing at all wrong with DIY room treatments. I suppose it is okay for DIY electronics, but not room tx...

Jim

Rclark · « **Reply #10 on:** 18 Apr 2013, 11:33 pm »

Quote from: medium jim on 18 Apr 2013, 11:29 pm

Don't blame you. You might also think about sewing and craft stores, like Michaels (I believe they're nationwide) as they might come in different colors.

Nothing at all wrong with DIY room treatments. I suppose it is okay for DIY electronics, but not room tx...

Jim

Yeah, it's pretty soft stuff, shouldn't be hard to make nice clean cuts, maybe paint em with something textured for some extra diffusion. They should be good for 300hz and up.

I'm just excited to kill that back wave. Should be able to do this pretty cheap, and make some simple stands for em, all that. At least to start.

jk@home · « **Reply #11 on:** 18 Apr 2013, 11:43 pm »

Also check into a hot wire foam cutter, Amazon has them pretty cheap. If weight isn't an issue, making the diffusers out of wood may be easier.

medium jim · « **Reply #12 on:** 18 Apr 2013, 11:43 pm »

Rclark:

It is more than just helping the 300hz and above, it will improve the soundstage by eliminating smear.

Let us know how it turns out. BTW, I did the same thing as I got some remnants from a recording studio (acoustic diamond shaped foam) that I used behind the Maggie's, this coupled with media storage on the front wall between the panels did wonders and made my room sound much larger.

Jim

Rclark · « **Reply #13 on:** 18 Apr 2013, 11:52 pm »

I believe it. I've read enough stuff on diffusers and Maggies, they seem to really like each other. No reason why I can't place these behind and push them around till I get something pleasing to the ear, then I can fine tune and measure later. I'm very very excited to take my Maggies further.

@JK, thanks, I'll probably just pick one up at Home Depot. Hoping to pick up the materials next Wed.

jk@home · « **Reply #14 on:** 19 Apr 2013, 12:08 am »

The pros here can correct me if I'm wrong, but AFAIK, the placement of the diffusers for the rear wave should be placed the same as one would do absorbers, in other words, get a mirror up against the wall and place the diffuser in the spot you see the back of the speaker (in the mirror) from your listening chair.

BTW, I feel your pain. I've been saving up for a couple of boxes of GIK foam diffusers. But now camping season is here and I need all sorts of stuff for the RV...

medium jim · « **Reply #15 on:** 19 Apr 2013, 12:13 am »

Quote from: jk@home on 19 Apr 2013, 12:08 am

The pros here can correct me if I'm wrong, but AFAIK, the placement of the diffusers for the rear wave should be placed the same as one would do absorbers, in other words, get a mirror up against the wall and place the diffuser in the spot you see the back of the speaker (in the mirror) from your listening chair.

BTW, I feel your pain. I've been saving up for a couple of boxes of GIK foam diffusers. But now camping season is here and I need all sorts of stuff for the RV...

That works for me....

Jim

Rclark · « **Reply #16 on:** 19 Apr 2013, 12:46 am »

Quote from: jk@home on 19 Apr 2013, 12:08 am

The pros here can correct me if I'm wrong, but AFAIK, the placement of the diffusers for the rear wave should be placed the same as one would do absorbers, in other words, get a mirror up against the wall and place the diffuser in the spot you see the back of the speaker (in the mirror) from your listening chair.

BTW, I feel your pain. I've been saving up for a couple of boxes of GIK foam diffusers. But now camping season is here and I need all sorts of stuff for the RV...

Nice.. thanks for the tip. My plan is to shove them as far back as possible against the back wall, as far from me as I can (and take away some toe in on my speakers and more straight on, to where that full back wave is hitting the diffusers). But, this is all new frontier type stuff.

PDR · « **Reply #17 on:** 19 Apr 2013, 01:05 am »

So is your plan to build one large panel or 2 separate ones.
You probably know about QRDude calculator, if not you do now.....

I work with styrofoam and used a hot wire table to cut mine, but
you would be better to cut it with a saw, a table saw would be best.

Youve prob seen this, but if not, heres a few shots of when I built mine.
There may be a tip or two in for you in there......HAVE FUN!! thats the main thing.
http://www.audiocircle.com/index.php?topic=96222.msg1035197#msg1035197

Rclark · « **Reply #18 on:** 19 Apr 2013, 02:02 am »

Quote from: PDR on 19 Apr 2013, 01:05 am

So is your plan to build one large panel or 2 separate ones.
You probably know about QRDude calculator, if not you do now.....

I work with styrofoam and used a hot wire table to cut mine, but
you would be better to cut it with a saw, a table saw would be best.

Youve prob seen this, but if not, heres a few shots of when I built mine.
There may be a tip or two in for you in there......HAVE FUN!! thats the main thing.
http://www.audiocircle.com/index.php?topic=96222.msg1035197#msg1035197

Always thought your listening space looked awesome. Yeah, that's about what I have pictured as far as the diffuser. I think I want to build 3 seperate panels and mess with them, place them all together, space them out, try all sorts of configurations.

studiotech · « **Reply #19 on:** 19 Apr 2013, 03:05 am »

The effective low frequency cut-off for the diffusor is as much about it's geometry as it is about the material it is made from. Typical QRD diffusors are really only effective to around 500hz for about 8" deep channels, so you're right to want several layers of foam glued up. Picts or it didn't happen....

Greg