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

Maritan · « **Reply #120 on:** 20 May 2013, 05:02 pm »

That diffuser looks like a lot of work.

And those Magnestands sure do look beautiful! Enjoy!

Rclark · « **Reply #121 on:** 20 May 2013, 05:31 pm »

Thank you very much!

They really are very pretty and deserve a better picture with better lighting. Looking forward to making some nice recordings of them in action as well. Anyway, about the diffuser, I'm looking forward to finishing and painting it. But I think I'll wait another week or so because an artist friend of mine is in the middle of painting for me a 40 inch by 30 inch Jimi Hendrix oil painting and the background is a bright orange color so I'll want to see which color might go with it best and not draw too much attention.

Hopefully today I can begin the skylines, which shouldn't be anywhere near as hard to build.

And next month I want to rent a truck and buy basstrap materials.

Rclark · « **Reply #122 on:** 20 May 2013, 11:31 pm »

Ok, so in marked contrast, skyline's are incredibly easy to build

I just built this whole thing from nothing in a matter of hours. 2' by 2' with 4" deepest well. It'll get sanded and cracks filled, painted. Another one built tommorrow. I didn't sand first, just wanted it built. It'll look much prettier.

Was a small fraction of the effort needed for that big qrd, and voila, skylines.

edit. glue's still wet so I was able to tighten up the lines. Looks nice.

neekomax · « **Reply #123 on:** 20 May 2013, 11:42 pm »

I had a lot of fun building a 'proof of concept' skyline diffuser out of 1x1 pieces of wood, glued to a piece of plywood. Came out looking awesome, but too small to be effective, and heavy as shit! I didn't use any kind of calculator, just made 1,2,3, and 4 inch sections and randomized as best I could.

Concept proven? Only that wood is too heavy.

medium jim · « **Reply #124 on:** 20 May 2013, 11:57 pm »

Quote from: neekomax on 20 May 2013, 11:42 pm

I had a lot of fun building a 'proof of concept' skyline diffuser out of 1x1 pieces of wood, glued to a piece of plywood. Came out looking awesome, but too small to be effective, and heavy as shit! I didn't use any kind of calculator, just made 1,2,3, and 4 inch sections and randomized as best I could.

Concept proven? Only that wood is too heavy.

Think Balsa Wood!

Jim

neekomax · « **Reply #125 on:** 21 May 2013, 12:26 am »

Quote from: medium jim on 20 May 2013, 11:57 pm

Think Balsa Wood!

Jim

I believe I did consider balsa wood... until I looked into the price.

Rclark · « **Reply #126 on:** 21 May 2013, 01:26 am »

The above diffuser cost less than $10

Rclark · « **Reply #127 on:** 21 May 2013, 08:46 am »

Holy. . Mackerel.

This stuff is so fun. Just got home from poker night and hung the single skyline a couple feet above my bed. Now, tomorrow night I'll have three of these.

The giant QRD is, as I said, providing huge dividends on that back wave, but I've been doing little tests as I go along and one of them is I clap my hands upon entering the room.

Even with my QRD, upon entering the room many feet from those and clapping my hands revealed some ringing.

I just clapped my hands with this single skyline added opposite the QRD, near me, and the clap sounded like it was coming much more from my hands, less from the echo. There is still some ringing, we'll see how that improves tommorow with two more.

Guy 13 · « **Reply #128 on:** 21 May 2013, 10:15 am »

Quote from: Rclark on 21 May 2013, 08:46 am

Holy. . Mackerel.

This stuff is so fun. Just got home from poker night and hung the single skyline a couple feet above my bed. Now, tomorrow night I'll have three of these.

The giant QRD is, as I said, providing huge dividends on that back wave, but I've been doing little tests as I go along and one of them is I clap my hands upon entering the room.

Even with my QRD, upon entering the room many feet from those and clapping my hands revealed some ringing.

I just clapped my hands with this single skyline added opposite the QRD, near me, and the clap sounded like it was coming much more from my hands, less from the echo. There is still some ringing, we'll see how that improves tommorow with two more.

Hi Rclark and all Audio Circle members.
Your project is super interesting for me and I am sure for other Audio Circle members.
Styrofoam here in Vietnam is inexpensive. (Super cheap)
Did you make the small styrofoam parts from a big board, let say 4' X 8' ?
Please let us know where you have hang up the diffusers in your room.

Guy 13

jk@home · « **Reply #129 on:** 21 May 2013, 01:39 pm »

RC, can you compare the QRDs with the same size of Skyline panels behind your Maggies?

neekomax · « **Reply #130 on:** 21 May 2013, 03:36 pm »

Rclark, you're inspiring DIY acoustics mania... my sub builds are next, as well as my tube preamp kit, but this thread has me stoked to do a few diffusers, too.

Speaking of, I just found the old thread where we were talking about building a skyline. I did not make 1", 2" cuts etc. I guess I found some dimensions somewhere, because I wrote this (in case anyone's thinking of doing one):

Quote from: neekomax on 22 Aug 2011, 07:59 pm

For a 2'x2' panel, the 2"x2" pieces are:

38 pieces - 1 7/8"
38 pieces - 3 3/4"
40 pieces - 5 5/8"
15 pieces - 7 1/2"

(This includes space for 13 blanks - 0").

http://www.audiocircle.com/index.php?topic=97780.msg981336#msg981336

Now I'm inspired to build a couple of foam ones, since they're so cheap and easy (although I'm not sure how easy painting will be...). Checked RPG prices and a 2'x2' is like $365!

Rclark · « **Reply #131 on:** 21 May 2013, 04:20 pm »

Quote from: jk@home on 21 May 2013, 01:39 pm

RC, can you compare the QRDs with the same size of Skyline panels behind your Maggies?

Hahahah hmmm no

. Now that would be a different story, and would take some time to build. But would certainly look really cool.

You know what, maybe in the future, after I'm set up to measure, I could build a giant skyline and compare it vs a QRD behind the Maggie.

@ Neekomax, yes, that's true, but the retail products are still worth it out of sheer convenience, and default build quality. I threw that first Skyline together to see how fast I could build it. When I go slower on these next two, and take finishing and painting into consideration, then you see that the RPG is a little steep, but probably worth it.

Can't say that for sure because I haven't bought one. For QRD's, definitely. The Realtraps diffuser is built with wood, and so is probably a bit more durable if you've got kids or if that's just a concern, although for me it isn't, and has fins which I assume let's it go higher.

Yeah, foam's great. Btw, I've been using Elmer's Wood Glue. Was told to use contact cement, but that stuff is brutal, and didn't want fumes. Wood glue dries strongly.

Rclark · « **Reply #132 on:** 21 May 2013, 04:48 pm »

Quote from: Guy 13 on 21 May 2013, 10:15 am

Hi Rclark and all Audio Circle members.
Your project is super interesting for me and I am sure for other Audio Circle members.
Styrofoam here in Vietnam is inexpensive. (Super cheap)
Did you make the small styrofoam parts from a big board, let say 4' X 8' ?
Please let us know where you have hang up the diffusers in your room.

Guy 13

Hi Guy

, yeah for the QRD I built from 1" deep, 4' by 2' panels. For the skylines I am cutting from 2" deep, 4' by 2' panels, the one's I'd mistakenly purchased initially.

I will take pictures eventually. The skyline is above me, a few feet away. I just threw it up there, completely unscientifically, but when I can measure I will fine tune this.

Rclark · « **Reply #133 on:** 21 May 2013, 08:48 pm »

Oh, and to answer your question Guy, I did nothing more than hammer a couple tiny nails into the backboard of the skyline diffuser, tied some fishing line to those, and nailed a picture hanger into the wall itself, and hung the diffuser from it's wire onto that. It's extremely lightweight so I just needed one.

SteveFord · « **Reply #134 on:** 21 May 2013, 09:33 pm »

Cool project - I'm looking forward to seeing the measurements.

Rclark · « **Reply #135 on:** 22 May 2013, 05:23 am »

Thanks Steve, me too. I'm going to look at inexpensive options to get REW up and running. And I will of course make sure to measure with everything removed as well.

Rclark · « **Reply #136 on:** 24 May 2013, 07:32 pm »

Absolutely amazing. I cannot believe how good this sounds. I finished a second skyline last night, and moved the two I have above me, directly in the path of each speaker. So big QRD way against the wall behind them, and now two skylines up front. The improvement with the two skylines added is just so cool. I noticed the effect before I even hit play. Was opening a popsicle and the crackling of the paper was loud, and this sounds were focused at the source rather than hearing the reflections as much. Very neat. The system sounds even better than it did.

Going to now build the last two of those for an 8' by 2' skyline array above me.

Rclark · « **Reply #137 on:** 24 May 2013, 10:56 pm »

WOOOOOOOOWW. Walked into my room after hanging the last two and spoke testing testing, etc, and my voice sounds very focused and close, not echoey at all. Playing some music and it all just sounds so good! I've run out of descriptors. Just incredible.

What I've gained with the skylines is just incredible focus. There's no impression of sound coming from the walls of my room anymore. It's a 3D, full bodied, eargasm with giant soundstage, resolution is increased, everything wow wow wow.

A further reduction in room-caused distorions, just an utter lack of any fatigue. It's all so organic and smooth. Bass is definitely being trapped by these. HIghs and cymbals are so crisp and decay in an instant. The bass is the most pleasant surprise of all. Definitely no need for a sub.

Here is a quick shot of the newly hung array. I rotated the faces to keep it random.

The pieces for the skyline weren't as precise as the QRD. Imperfections in the 2" panels caused this. So there are some little gaps you can see here and there.

Bought expanding foam to take care of all that, and smooth out the faces. Then paint.

For those with Magnepan systems I absolutely recommend large scale diffusion. It's a huge, huge upgrade.

Maritan · « **Reply #138 on:** 25 May 2013, 02:47 pm »

Nice progress. So, you have diffusion behind the speakers and behind your head/ listening position. Do you have any treatments on the side walls?

Rclark · « **Reply #139 on:** 26 May 2013, 05:25 am »

No I don't, and there is still ringing when I clap my hands. My speakers are dipoles, and don't really care about the sidwalls so much, but there are still improvement to be had for sure.

But if I don't touch my saw for a while or look at styrofoam panels any time soon I'll be good. In June I plan on building corner superchunks, and I think that will be a very easy, quick project.

Might also build some traps to pehaps build a cloud. I've heard that removing the ceiling accoustically brings some of the biggest benefits.

I also want, perhaps desperately, a Dspeaker Dual Core 2.0, but it's out of the budget for the time being. That should bring some good dividends on the bass.

Meanwhile I'll try and get a cheap soundcard and microphone soon, just to make some measurements, although, at this point they should just confirm what I'm hearing.