Some Serious QRD

[Lonely Raven]

I don't believe I've seen these photos anywhere in the forums (not that I've been to every corner), but since I stumbled into these photos again I figured I'd share them.

Check out this very serious 2 channel room!

Original Link here: SoundScapeS Compromisloze Luisterruimte: Het Plan

Damn, photos won't show... You'll have to follow the link and check it out yourself!

Thoughts?

[Lonely Raven]

I borrowed one of their photos and put it up on my server...this is some fantastic work!



While I can't read the page, I understand a lot of what is going on from a woodworking standpoint. It looks like they even had their own custom shaper blades made to mill out the inside panels for the "nested" type of QRD.

Amazing work.

[gremmy]

Looks pretty cool to me! I'd love to hear what the room sounds like.

[PaulP]

Here are all the gory details :

http://www.soundscapes.nu/!gallery/design/index.htm

For the shaper blades, I think it would be possible on a stationary spindle
shaper to just stack a bunch of rabetting cutters with spacers between to
get the proper shape. It would take a fair sized shaper.

A lot of food for thought in those pictures. Thanks thumbsup.

Paul P

[Lonely Raven]

Originally Posted by PaulP

Here are all the gory details :

http://www.soundscapes.nu/!gallery/design/index.htm

For the shaper blades, I think it would be possible on a stationary spindle
shaper to just stack a bunch of rabetting cutters with spacers between to
get the proper shape. It would take a fair sized shaper.

A lot of food for thought in those pictures. Thanks thumbsup.

Paul P

Exactly on both points.

Can you believe they built this bunker just for two channel listening!!

I'm surprised they made the walls parallel. Maybe they figured it would be easier to design around a rectangular bunker than work with sloped walls.

Radiating heating in the floors, box-inside-a-box building design for sound proofing, and wall to wall diffusers with some supersized helmholtz slats. I wonder if they built the room on the golden ratio...that would make sense if they did.

I've been in a similarly treated room, but to a much, much smaller extent. And it was hands down the best, most holographic sound I've ever heard. And it wasn't even flat frequency in that room, just well treated time wise. Even on really old CD, recordings of early Van Halen...you could pick out each layer of each track, every voice in the chorus, and everything floated in the room. The details were astounding. And all that was on a $500 pair of home made two way speakers, home made speaker cables, home made 3 watt SET, from a $500 beat up old Denon CD player. The guy that owned the room said it was even better with vinyl!

So I can imagine what the room linked in this thread sounds like...but to a much, much better extent. It would be truly life changing to hear a room like this...the small room I heard certainly was to me, and I've never it's rival since.

[collo]

Nice find LR,

As PaulP points out, it's well worth following their link to the gallery section

There are some great mounting ideas. I liked the feet (probably adjustable, like those used for kitchen cupboards) for the wall mounted diffusers, and the strong rods used for the roof-mounted diffractals.

I bet it cost 'em a motza to run those diffractal inserts!

I did wonder why they packed the back cavities with insulation, given that the timber used was quite thick and would be unlikely to pass much energy. Also why were the roof diffusers aligned along the room rather than across it? Always a little mystery with the goodies!


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The images have hotlink protection, so you can't just point to them from this thread (guards against "bandwidth theft")

This also prevents the images showing up when viewing the site via the "Translate" option from Google's search results.

You can however see the text in English plus the pictures, if you have the Google toolbar installed and use the toolbar's built-in translate function.

Amongst the gems to be had if you go to this trouble are statements like:

"The three small pictures below to see how using a heavy crane to two Mark Levinson amplifiers (160kg. each), neatly packed in a wooden box from the attic window to be lifted."
also ....
"There is about 3000 pounds of diffusers on the ceiling to hang ....." crikey!!!

[Lonely Raven]

And I thought my 200lbs of diffusers on my back wall was heavy! LOL

I found that page about a year ago, and I was hoping to stumble into it again. I'm glad I did. I wish I could talk with the designer a bit to get some clarification on some things...

As for the expanding foam...I've used this myself to keep the chambers from resonating and causing problems. Maybe they were making sure the chambers behind the diffusers were quiet, or maybe they wanted to control the amount of absorption those chambers might cause?

[PaulP]

There's a lot more great stuff on the site if you go up to the root of the site and back down
in the various projects. How about a round ceiling QRD : SoundScapeS -- ronde diffuser

Paul P

[Nordenstam]

Glorious room and diffusers!

Originally Posted by collo

Also why were the roof diffusers aligned along the room rather than across it? Always a little mystery with the goodies!

Mayhap they wanted the sound from the speakers to hit the back wall before it's being diffused?

[collo]

that would be this one...

[Nordenstam]

Neat! The diffuser book mentions it as a way to decrease distance needed to attain far field response.

[Lonely Raven]

Seeing all this stuff being built and installed is like porn to me.

I can hardly wait to get back into the shop and work on all my 1D and 2D and Skyline diffusers!!

[terry j]

yeah. Gonna go on a limb here and say 'for guys like us, that IS a porn site'.

Hmm, what does that say about us??

WAF phooey, any chick that does not get horny in a room like that is not a chick for me!!

Something about 1d qrds....rrrr, (and when I'm finished it's)

[PaulP]

Here's an interesting item from the same site, a CD rack / bookshelf diffusor
(yes, there's a diffusor under the fabric) :

SoundScapeS diffuser. (Construction details are lower down on the page)

Here are some interesting photos of the treatment of a small garage size room with wall to
wall diffusors hidden under fabric (the last few pictures in the list).

Paul P

[Lonely Raven]

Paul, a bunch of those images in that gallery link you posted, are borrowed from elsewhere. I recognize some from Decware and other sources I've seen over the years. It looks like there are some of those "folded" QRD....where the deepest wells are L shaped to get the deep wells in a shallow depth.

I was never sure if that would work or not. I've had people poo-poo that design, but then we've all been wrong on acoustics points before.

[terry j]

pretty sure well folding is in the bible, so should be OK.

[PaulP]

Here's yet another take on QRD diffusers :

See a bit more on the project at ESPACE.

Paul P

[SAC]

Folded wells have always been fine - just use a bisecting centerline to determine depth.

And glass QRDs were among the first materials used commercially - as high cost, mass, and difficulty with material handling and on site construction (and the need to use tempered glass in many situations) run the costs up rather quickly.

Also, in regards to the interspersed bookcase and 2D QRD, one would be better served making a separate shelf and more contiguous higher order QRD as the QRD order as implemented would not be artificially and arbitrarily constrained to N=2 or 3 (!!!) as it is in the example.

Aesthetics are always nice, but such a radical limitation of the functional aspects of large areas of the design render the QRD little more than artwork with VERY limited acoustic value. Personally I would opt for greater function.

But in all cases, and in far too many threads, the question seems to revolve around simply the desire to ad additional diffusion. In few cases has anyone actually evaluated the soundfield and determined what aspect of the soundfield needs to be tailored and how, and from this evaluation then evaluated the response of the room to determine optimal placement and exactly how one plans to redirect the energy in a larger frame of reference.

I like diffusion. But that alone is not sufficient. Diffusion is useful as a tool used to modify the soundfield response in a particular controlled manner. One is not obtaining the optimal benefit if it is employed as a simply as the result of a pent up emotional 'need' (as in: We Need some diffusion! The lack of which simply bothers me!).

Thus what is necessary is the understanding of various room models and the use of the tools that allow us to evaluate and relate the room's subjective perceptual experience to the objective behavior. And from there, using best practices, target established 'standards' that provide a baseline for the room's response - rather than simply 'making random changes' that may serendipitously enhance or impede a room's response.

So, to play the devil's advocate, I like diffusion. But diffusion is not an end response in itself. It is but one, albeit powerful, tool. And it is best employed in the context of a larger plan where its design and function augments and furthers the overall design of a desirable soundfield response. And thus far, only 2 or 3 folks here have attempted to employ such a concept...It would indeed be nice to see even more become interested in this larger aspect that moves beyond a focus on the tool itself often examined out of context. An awareness of the larger context of the overall room response will largely determine which diffusor variant (design, material, placement, etc.) is optimal dependent upon the desired impact upon the soundfield energy.