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Message started by Lonely Raven on 06/04/14 at 16:02:35

Title: Getting back to building diffusers
Post by Lonely Raven on 06/04/14 at 16:02:35


I've started working on diffusers again. Since I need a CNC Router to make the jig I need for the Prime 31 QRD diffuser I've designed. I did a dumbed down design for this proof of concept. This is a Prime 11, 6" deep, with 2" wide wells. It's pretty much a 24" by 48" prime 11 diffuser.


Title: Re: Getting back to building diffusers
Post by 4krow on 06/04/14 at 22:44:13

When I think about diffusers, it kind of blows my mind. This happens because of the variety of materials that could be used, and their arrangement. Of course, that makes me wonder what would be best and why. I get overwhelmed and switched another thought. Why don't I just buy magical cables, and all of my problems go away?

Title: Re: Getting back to building diffusers
Post by Lonely Raven on 06/06/14 at 15:21:30

I've been trying to find this video since it was released about a year ago. and just stumbled into it today.

It's a neat experiment that visually shows the harmonics, or modes that sound is creating on this plate. Now, if you take this, and imagine it in a cube, *that* is why we have sound absorbers and diffusers. Those nodes, or hot and dead spots are what mess with the frequency response at our listening position.

https://www.youtube.com/watch?v=1yaqUI4b974


Title: Re: Getting back to building diffusers
Post by Lonely Raven on 06/20/14 at 20:00:42


I got my jig made last weekend, but I've not had time to start cutting tops and bottoms for my fleet of diffusers. I hope to start that this weekend. I'm thinking some hardwood and plywood ones to start. Basically whatever materials I have on hand. Make a few prototypes, get into the swing of cutting. Next, I have to make an assembly jig. This will basically be a panel with wood or foam blocks set to the correct depth needed for each well. That way, I take all my parts, set them on the assembly jig, and simply start gluing it all together. If all goes well, (and I can afford it) think I could start making two of these a week.

The Jig for step one!  :)


Title: Re: Getting back to building diffusers
Post by Acetone on 11/21/14 at 16:47:53

Hey L Raven,   Is your diffusion build complete?  I've installed absorbtion bit by bit over the last 4 months....trying to sneak up on a well tuned room.  next step will be 1st reflection on ceiling, then I will start thinking about diffusion. Interested to know more details of you room and experiences with acoustic treatments.

Title: Re: Getting back to building diffusers
Post by Lonely Raven on 12/01/14 at 17:02:20


I had to put my duffers on pause for house projects. We are demoing our basement, and further working on replacing the aluminum wire we found in our house with copper. All this has pretty much trashed my garage workshop since half the basement got stored in the garage.

My design is pretty amazing, nobody makes anything this broadband (off the shelf). It's also very complicated to build. I've got two version I'm working on to see which is easier to build. Once I get a build method down, I need to build about 24 of these 12" (deep) 30" X 36" diffusers, and at a cost of approximately $115 each, not including replacing/sharpening table saw blade, glue, screws and whatever. If I wasn't pushing myself to make such a crazy-complex diffuser, I'd have had these done a year ago.

Over-engineering/Overbuilding is a fault of mine.

Title: Re: Getting back to building diffusers
Post by Acetone on 12/01/14 at 22:53:29

Wow! that's a lot of diffusers. But, I've seen a few of your room pics and understand there's a lot of sq/ft to cover. My room is only 11' x 16' x 8 H. So not a lot to cover, just deciding what to do, and where to put it. This is my retirement project so I have 18 months of tweaking if I want it done by then. But, as many have stated in these forums...is ever done?

Title: Re: Getting back to building diffusers
Post by Lonely Raven on 12/03/14 at 19:53:08


Diffuser placement is pretty easy to start with.

IMHO, you should have diffusers on *all* first reflection points, including the ceiling. At every least, I would have diffusers between the speaker on the front wall, on the back wall, and first reflections on the side wall.

What's great about covering those four points, is that you're getting more than just 4 reflection points, because the diffusers will catch secondary reflections from other diffusers, as well as untreated parts of the room...which is often why ceilings get left alone.

Then you build yourself several sound absorber panels to cover other areas, act as bass traps, and you can do most of your fine tuning by ear.

I threw some (similar) ideas at Palomino, and he's cobbled together some traps and poly-cylindrical "diffusers" (using the term very loosely), and I think he's even done a couple small skyline diffusers for fun, and through some suggestions, and mostly his tuning by ear, he has some of the best imaging I've ever heard. And I swear to you his *whole system* costs less than what I paid for my ZMA!

Sound treatment is where I'm failing miserably. I need to either move my system to a dedicated room, and wing the sound treatment like he did, or get off my arse and build a fleet of diffusers to help fix my dreaded "L shaped room"

Title: Re: Getting back to building diffusers
Post by Acetone on 12/03/14 at 21:58:23

LR,  thanks much for the info. Since my room is so small I wonder about diffusion in 1st reflections...11' x 16' x 8'.  I've read so much it makes my head spin. Guess I'll give Steve a call when I have the funds to take next step(s). A lot to consider going forward.

Title: Re: Getting back to building diffusers
Post by Lonely Raven on 12/05/14 at 05:13:55

11 X 16 is a very respectable room. If you were saying 9 X 8 or something, then I'd say yeah, you've got problems.

The only thing to keep in mind with diffusers, is that you need a few feet between them and your ears for them to disperse the sound evenly. Otherwise you could get some peaky diffusion. The diffusers Steve sells (or maybe only sells plans to now? I've not looked in ages) are a great compromise as they cover the upper ranges where diffusers are most effective, and they only need a couple feet between them and your ears.

https://www.decware.com/p1312.htm

Don't get scared off from diffusers, they can do so much more then absorbers, and they help keep the sound energy in the room, rather then dumping it into an absorber. They also help keep your frequencies even while keeping the room live.

Title: Re: Getting back to building diffusers
Post by Acetone on 12/08/14 at 19:35:18

Thanks LR...good to know. I will be saving for a few pair that I will likely put on back wall - behind speakers. Then play with more placement when I am able to purchase more diffusion! Basically going over budget, but I believe the pay off will be worth it.

Title: Re: Getting back to building diffusers
Post by Lonely Raven on 12/09/14 at 15:21:10


If I had the cash, i wouldn't even flinch from paying twice what my speakers cost on room treatment. It makes that much of a difference.

Title: Re: Getting back to building diffusers
Post by Lon on 12/09/14 at 15:51:56

You're lucky that you own a home and have acceptance/permission from Brianne to set up room treatments. I've never had both at the same time and probably won't. That said, there are other ways to skin a cat and I've my share of successful hides. :) It's also part of why I don't strive for perfect playback as without going that route what's the point?

I'm glad I don't actually because as exploratory and fidgety as I am without treatment I would probably be even worse with treatment, and I find that this part of the hobby takes me further away from musical enjoyment than I'd like. I'm always struggling to swing the balance back towards just relaxing and listening and from analyzing and tweaking. When I had more time it was a luxury that is now impinging on my real listening time.

Title: Re: Getting back to building diffusers
Post by Acetone on 12/19/14 at 00:21:07

Lon, I hear you there.  I've spent >800 on absorbers and will now add diffusion. It's a 2 + year project (retiring mid 2016'). I hope to have everything set by then so I may sit, listen and enjoy!  Diffusion, better cartridge, power regeneration, nos tubes all on the wish list with 18+ months to go.

Title: Re: Getting back to building diffusers
Post by Lon on 12/19/14 at 04:03:18

Ambitious and excellent plans. Hope they come to fruition! :)

Title: Re: Getting back to building diffusers
Post by Lonely Raven on 12/21/14 at 15:58:19

Acetone, that sound like an awesome plan!

Keep posting about your progress in the forums!

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