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

Rclark · « **Reply #140 on:** 26 May 2013, 05:44 am »

I'm also considering a second 8' by 2' skyline above the one I have now. Why not? Also now considering completely sealing off my closet there and doing a floor to ceiling QRD. But, oh man, no more cutting styrofoam, not for a while.

srlaudio · « **Reply #141 on:** 30 May 2013, 10:25 pm »

I like your concepts. I studied your pictures however and echo the previous observations that they are not matching the symmetry of standard diffusers. You may have had the offset wheel in QRD in a non standard position. Another thing is I have have found it is best in 8 or 10 foot width to make the diffuser one sequence, that is raise the prime number and play with the channel widths to optimize the design. To really impact the bass, make the depth 11 inches or greater. The material at Home Depot is low density EPS. Probably 1 lb or less. I use high density material ie 3 lb which makes for a sturdier unit with more mass. These type qrd units can be lined up and stacked floor to ceiling for fantastic effect. I am involved right now in making a 10 ft wide 40 feet tall qrd for a church sanctuary front wall. Good luck with your project, I hope to hear from you in the future!

Rclark · « **Reply #142 on:** 30 May 2013, 11:26 pm »

Hey

I kept the wheel at zero. And according to the reading provided by the calculator, 3+ panels and 1 - panel is okay, but since I am keeping it as one large one, I probably should have just made one sequence. But if you go back a few pages, you'll see that I kept the wheel at zero offset.

I'm at about 11 inch depth, so as you say, that must be what is impacting the bass. You're right though, it's fairly low density stuff.

I was about to make a post and say how nice everything is sounding. It sounds like the music is taking place in this giant ball of plasma around the system now, rather than reflecting from the walls. So they are definitely working. Will measure soon! There is definitely improved decay, improved everything.

Love your stuff! Hope to see you have more of a presence here.

srlaudio · « **Reply #143 on:** 8 Jun 2013, 02:53 pm »

I appreciate your comment! Your observations are in line with my experiences. Nothing I have tried has improved room performance like large diffusers. In the past I have been handed my head around here for suggesting that bass standing waves can be mitigated with large enough diffusers. Now some of those naysayers are are preaching the same thing! The weight of the truth has more mass than hot air.....
I would be interested to see the outcome of your measurements. Your efforts reveal a real love for music and high performance audio!

Rclark · « **Reply #144 on:** 10 Jul 2013, 07:52 am »

so......

I basically finished this project over a month ago. Since that time occurred.. I never think about gear, never crave the forum for information..

I just listen to music. I've definitely reached a nice plateau in audio nirvana. Constantly gobsmacked.

Rob Babcock · « **Reply #145 on:** 11 Jul 2013, 06:54 am »

That's kind of the Holy Grail!

It's great when you have a room that lets the music "breathe" a bit. The gear can get out of the way!

Rob Babcock · « **Reply #146 on:** 11 Jul 2013, 07:06 am »

BTW, RClark, would you like me to sticky this thread? Lots of good info here!

Rclark · « **Reply #147 on:** 11 Jul 2013, 10:12 pm »

Go for it, that's great

. It's time for me to get serious again and buy more gear, a measurement rig, and start on basstrapping.

emailtim · « **Reply #148 on:** 22 Jul 2013, 06:21 am »

Quote from: Rclark on 10 Jul 2013, 07:52 am

so......

I basically finished this project over a month ago. Since that time occurred.. I never think about gear, never crave the forum for information..

I just listen to music. I've definitely reached a nice plateau in audio nirvana. Constantly gobsmacked.

Any final pictures?

Did you keep your prototypes, or did you make new sets?

Did you ever use Fins+Wells, or just the Wells as seen in your prototype pictures?

Did you coat them with anything or paint them?

TIA

srlaudio · « **Reply #149 on:** 15 Sep 2013, 02:38 am »

I have some more information for you...... I have painted styrofoam diffusers with high quality latex AND enamel paint. The enamel was actually very expensive, was designed to paint wrought iron fences, and I had NO problems with the "eating away" of anything. I had to use two coats to get the look I wanted, so now I start with a coat of Kilz original primer, then a finish coat of either latex or enamel. So really your finish options are larger than you thought.

Rclark · « **Reply #150 on:** 18 Oct 2013, 10:55 pm »

Quote from: emailtim on 22 Jul 2013, 06:21 am

Any final pictures?

Did you keep your prototypes, or did you make new sets?

Did you ever use Fins+Wells, or just the Wells as seen in your prototype pictures?

Did you coat them with anything or paint them?

TIA

Hey! I've moved, and sort of went into other interests for a bit. The diffusers had put my system at pretty much the level I'd been dreaming of when I started this hobby. Now I'm in a smaller space, and will soon be focusing on bass trapping and room correction as this room is a bit tight.

Decided I'm not going to paint these. My plan is to slowly replace the large diffusers with fully built retail units down the road, or build large units from wood with fins, etc. These will last in the meanwhile though.

They are a massive upgrade and definitely helped the Maggies a lot!

TRADERXFAN · « **Reply #151 on:** 19 Oct 2013, 12:52 am »

Curious, why replace with the retail units after you already did all that work?

Rclark · « **Reply #152 on:** 19 Oct 2013, 04:44 am »

Oh it wouldn't be for a long time. Just to have something furniture grade rather than diy. This build was mostly to affirm whether they made a difference or not, and to not spend too much.

bwaslo · « **Reply #153 on:** 7 Jan 2015, 08:56 am »

On the subject of DIY diffusers--

I recently came across this website by Tim Perry-- http://arqen.com/acoustics/acoustic-diffusers/

Tim has come up with some very easy to build, quite inexpensive wood diffuser designs, particularly his "LeanFuser"s. I made a variation on these, varied because I'm in an "imperial unit" (inches) country with different nominal lumber sizes and wanted to use low-cost furring type lumber pieces. I used the AFMG Reflex evaluation program (as Tim suggested) to hand-optimize a 14-board wide diffuser based on his 7-board wide LeanFuser. I got all the wood pieces cut at Home Depot (cut for free!) and for under $100 got all the wood and panels to make 2.5 sets of 40" high by 35"wide diffusers. These are "step diffusers" which don't use the vertical wells of a QRD type diffuser and are less lossy than those types as well. And MUCH easier to assemble. With all the wood pre-cut, a little time beforehand marking up the ply panels with a pencil and ruler, and an electric 1.25" brad gun, it took under an hour to assemble them. Very fast to do and they look pretty nice, considering. They'd look better if I polyurethane'd them, but that's for later.

These covered an otherwise open section of concrete wall at the first reflection points of the loudspeakers. I was expecting an improvement to sound, but not this degree. It really made a great difference to the sound of the room. Previously it had been over-damped. I had filled in the beams in the (too low) ceiling above with absorbent covered with burlap. With the diffusers added, the sound became both more lush and much more detailed.

Highly recommended, if you have the freedom to put up something like these in your room.

edit: attached is a (crummy) phone shot of the basement listening room-in-progress, with the first-try diffusers set up. I'll be doing some floor-to-ceiling ones for the back of the room later.

gregfisk · « **Reply #154 on:** 7 Jan 2015, 07:13 pm »

Quote from: bwaslo on 7 Jan 2015, 08:56 am

On the subject of DIY diffusers--

I recently came across this website by Tim Perry-- http://arqen.com/acoustics/acoustic-diffusers/

Tim has come up with some very easy to build, quite inexpensive wood diffuser designs, particularly his "LeanFuser"s. I made a variation on these, varied because I'm in an "imperial unit" (inches) country with different nominal lumber sizes and wanted to use low-cost furring type lumber pieces. I used the AFMG Reflex evaluation program (as Tim suggested) to hand-optimize a 14-board wide diffuser based on his 7-board wide LeanFuser. I got all the wood pieces cut at Home Depot (cut for free!) and for under $100 got all the wood and panels to make 2.5 sets of 40" high by 35"wide diffusers. These are "step diffusers" which don't use the vertical wells of a QRD type diffuser and are less lossy than those types as well. And MUCH easier to assemble. With all the wood pre-cut, a little time beforehand marking up the ply panels with a pencil and ruler, and an electric 1.25" brad gun, it took under an hour to assemble them. Very fast to do and they look pretty nice, considering. They'd look better if I polyurethane'd them, but that's for later.

These covered an otherwise open section of concrete wall at the first reflection points of the loudspeakers. I was expecting an improvement to sound, but not this degree. It really made a great difference to the sound of the room. Previously it had been over-damped. I had filled in the beams in the (too low) ceiling above with absorbent covered with burlap. With the diffusers added, the sound became both more lush and much more detailed.

Highly recommended, if you have the freedom to put up something like these in your room.

What a great website, thank you for posting it. These look much easier to build and my understanding is the harder materials such at wood make much better diffusers.

Greg

jk@home · « **Reply #155 on:** 5 Mar 2015, 06:49 pm »

I'm in the process of painting some Styrofoam diffursors, having to do it via hand brushes and wanted to pass on a tip.

I've never been a fan of those cheap foam brushes, but have found them to work great in getting between and paint on the vertical sides of the fins, where a polyester bristle brush would have difficulties.

I just load up both sides of the brush, and can brush vertically and horizontally to basically "rub" the paint on. Then I finish up with a regular thin brush to smooth things out, catch any runs, and wick up any excess paint. Really a time saver.

jk@home · « **Reply #156 on:** 7 Mar 2015, 03:43 pm »

And the finished product. These are "semi-diy" as the diffusers came as 2 x 2 units from SRL (bought over a year ago). Still, it was quite a bit of work to join, machine plum to fit the boxes, seal the edges and centers and paint. One coat of latex primer and three coats of latex flat wall paint (same color as the walls and ceiling of room). Got it down to two hours per coat per panel. Mounted in 1 x 8 diy oak boxes, on modified Sound Anchor stands (for Maggie MMGs) and casters.

Here's a pic of the room, with the finished diffusers and diy absorbers:

http://www.audiocircle.com/index.php?topic=128954.20

gregfisk · « **Reply #157 on:** 7 Mar 2015, 04:21 pm »

Quote from: jk@home on 7 Mar 2015, 03:43 pm

And the finished product. These are "semi-diy" as the diffusers came as 2 x 2 units from SRL (bought over a year ago). Still, it was quite a bit of work to join, machine plum to fit the boxes, seal the edges and centers and paint. One coat of latex primer and three coats of latex flat wall paint (same as walls and ceiling of room). Got it down to two hours per coat per panel. Mounted in 1 x 8 diy oak boxes, on modified Sound Anchor stands (for Maggie MMGs) and casters.

Here's a pic of the room, with the finished diffusers and diy absorbers:

http://www.audiocircle.com/index.php?topic=128954.20

Nice project, wondering what they do for the sound. I'm looking at options for room treatment and would like your opinion if you get a chance.

Thanks,

Greg

jk@home · « **Reply #158 on:** 7 Mar 2015, 05:30 pm »

They made a big difference when I was running dipoles in the room (small Magnepans) They really helped tame the backwave of the speakers from over powering the small room. Comb filtering and such.

With the KEFs, they still seem to add a bit of depth to the sound stage, and add the highs back to the room after all the absorption panels were installed.

jimtranr · « **Reply #159 on:** 7 Mar 2015, 10:00 pm »

Quote from: bwaslo on 7 Jan 2015, 08:56 am

I recently came across this website by Tim Perry-- http://arqen.com/acoustics/acoustic-diffusers/

Thanks for the link, Bill.

Look forward to the photo(s) of the back-of-the-room diffusers after you put them together.

Jim