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-   -   Bookshelf Diffuser ? (https://gearspace.com/board/studio-building-acoustics/635956-bookshelf-diffuser.html)

Philip Eno 3rd August 2011 01:34 PM

Bookshelf Diffuser ?
 
Has anybody experimented with building a bookshelf in the general shape of a diffuser?

I'm a composer and keyboardist and I'm quite ignorant about acoustics. I need to treat my rehearsal room and at the same time, I need a space for some books. I was wondering if it were possible to design a bookshelf that will make it as good as a diffuser.

localhost127 3rd August 2011 02:24 PM

Quote:

Originally Posted by Philip Eno (Post 6903948)
Has anybody experimented with building a bookshelf in the general shape of a diffuser?

I'm a composer and keyboardist and I'm quite ignorant about acoustics. I need to treat my rehearsal room and at the same time, I need a space for some books. I was wondering if it were possible to design a bookshelf that will make it as good as a diffuser.

free 30-day trial.
Features - AFMG Reflex

measure your bookshelf. width of books (well depth), and the position you have them in. model into AMFG Reflex and render.

this puts all 'guesswork' to rest for those wanting to use bookshelves as diffusers.

it would also help to read the QRD Tech Guide to gain a better understanding of how the well width, period width, well depth, angle of incidence, etc --- all impact the working freq-range of the diffuser.

QRD diffusers: Technical Overview

you'll likely discover why QRDs work so well and why many people do not use bookshelves as diffusers - and instead design proper QRD/PRDs to their own custom design specs.

aackthpt 3rd August 2011 03:26 PM

Also remember that almost all materials have some absorption, and that all devices are mixed devices - it's just a matter of how much of one characteristic they posses versus another. I've never looked it up, but my guess would be that a shelf of books would wind up being more of a midrange absorber than any sort of scattering or diffusing device. Though it probably wouldn't do any of it especially much.

For best diffusion effect, you'd also have to keep the books in precisely the same positions and at precisely the same depths all the time. Unless you never actually use the books, that seems unlikely.

boggy 3rd August 2011 03:48 PM

Quote:

Originally Posted by Philip Eno (Post 6903948)
Has anybody experimented with building a bookshelf in the general shape of a diffuser?

I'm a composer and keyboardist and I'm quite ignorant about acoustics. I need to treat my rehearsal room and at the same time, I need a space for some books. I was wondering if it were possible to design a bookshelf that will make it as good as a diffuser.

Only diffusers can't help your room. If you can assign books in shape of amplitude grating diffuser, like some binary diffuser construction, this can allow air circulation to your LF treatment behind your book shelf. And this will work well...
Quote:

Originally Posted by localhost127 (Post 6904061)
free 30-day trial.
Features - AFMG Reflex

measure your bookshelf. width of books (well depth), and the position you have them in. model into AMFG Reflex and render.
........

It's a shame that AFMG Reflex can't do amplitude grating type of diffusers, or well can't be changed to be absorptive... AFAIK.



Philip, with some air circulation between books, for thick LF absorption behind, you can pack some pretty serious acoustical treatment with this book shelf.
Only drawback is that each book will have its unique place...

Glenn Kuras 3rd August 2011 04:17 PM

A few years ago we tried to design a CD case that would be a diffusor but the thing became pretty deep and not practical.

boggy 3rd August 2011 04:22 PM

Quote:

Originally Posted by Glenn Kuras (Post 6904320)
A few years ago we tried to design a CD case that would be a diffusor but the thing became pretty deep and not practical.

Did you try an amplitude grating construction? Something similar to BAD panel from RPG, but not with square holes...

Glenn Kuras 3rd August 2011 04:27 PM

Quote:

Originally Posted by boggy (Post 6904328)
Did you try an amplitude grating construction? Something similar to BAD panel from RPG, but not with square holes...

No we did a QRD. Basically made a metal grid you would slide the CDs in. May look at a amplitude grating in the future. It was a cool idea to try but like I said it just became way to deep as a shelf. But then again we where trying to make it the full CD in depth. shiee

boggy 3rd August 2011 04:31 PM

Quote:

Originally Posted by Glenn Kuras (Post 6904345)
No we did a QRD. Basically made a metal grid you would slide the CDs in.

You can't easily reach cd's from deep wells ... non really practical...
Quote:

Originally Posted by Glenn Kuras (Post 6904345)
May look at a amplitude grating in the future. It was a cool idea to try but like I said it just became way to deep as a shelf. But then again we where trying to make it the full CD in depth. shiee

It can be deep as ordinary shelf, but only half of a capacity... for 100cd's you need a space of 200cds... that is a reasonable compromise, IMHO.
I'm only scared for noises and resonances that CD boxes can make when vibrate... that wouldn't be a good thing. Books are pretty quiet and dampened....

Glenn Kuras 3rd August 2011 06:56 PM

Quote:

Originally Posted by boggy (Post 6904354)
You can't easily reach cd's from deep wells ... non really practical...

It can be deep as ordinary shelf, but only half of a capacity... for 100cd's you need a space of 200cds... that is a reasonable compromise, IMHO.
I'm only scared for noises and resonances that CD boxes can make when vibrate... that wouldn't be a good thing. Books are pretty quiet and dampened....

But books could actually absorb and having the same size books is pretty hard. All and all a cool idea, either way, but not as practical as one would think. We are always throwing mud on the wall to see what might stick. Half of the fun is coming up with new products. kfhkh

boggy 3rd August 2011 08:27 PM

Quote:

Originally Posted by Glenn Kuras (Post 6904771)
But books could actually absorb and having the same size books is pretty hard.

I'm sure that Philip likes his books more than any our acoustic device, and it's always some challenge to hide acoustic treatment in some living/working space, at least... it's sometimes worth to try
Quote:

Originally Posted by Glenn Kuras (Post 6904771)
All and all a cool idea, either way, but not as practical as one would think. We are always throwing mud on the wall to see what might stick. Half of the fun is coming up with new products. kfhkh

Yup... it's cool to discuss something new (not always useful of course... heh ), this is a public forum cooge

Philip Eno 5th August 2011 10:02 PM

Quote:

Originally Posted by localhost127 (Post 6904061)
free 30-day trial.
Features - AFMG Reflex

measure your bookshelf. width of books (well depth), and the position you have them in. model into AMFG Reflex and render.

this puts all 'guesswork' to rest for those wanting to use bookshelves as diffusers.

it would also help to read the QRD Tech Guide to gain a better understanding of how the well width, period width, well depth, angle of incidence, etc --- all impact the working freq-range of the diffuser.

QRD diffusers: Technical Overview

you'll likely discover why QRDs work so well and why many people do not use bookshelves as diffusers - and instead design proper QRD/PRDs to their own custom design specs.

Thanks for the links. I think I need to do much more research to understand the theory and math before I even try AFMG Reflex, so I'll work on that.

Looks like I might just abandon the bookshelf idea and work on a QRD that fits my needs. Thanks again!

Philip Eno 5th August 2011 10:04 PM

Quote:

Originally Posted by aackthpt (Post 6904200)
Also remember that almost all materials have some absorption, and that all devices are mixed devices - it's just a matter of how much of one characteristic they posses versus another. I've never looked it up, but my guess would be that a shelf of books would wind up being more of a midrange absorber than any sort of scattering or diffusing device. Though it probably wouldn't do any of it especially much.

For best diffusion effect, you'd also have to keep the books in precisely the same positions and at precisely the same depths all the time. Unless you never actually use the books, that seems unlikely.

Hmmm. I do need to use the books so if I need to have them in the same place all the time, I'd have a really hard time. So I guess that's out of the question. Thanks!

Philip Eno 5th August 2011 10:14 PM

Quote:

Originally Posted by boggy (Post 6905075)
I'm sure that Philip likes his books more than any our acoustic device, and it's always some challenge to hide acoustic treatment in some living/working space, at least... it's sometimes worth to try

Yup... it's cool to discuss something new (not always useful of course... heh ), this is a public forum cooge

Boggy,

Yes I think you understand what I'm trying to do. I'm trying to keep the place as homey as possible at the same time making it sound quite good. It's a home studio and it's (psychologically) important for me to rehearse with that kind of atmosphere.

Right now, I'm trying to read up on acoustics (I'm completely ignorant about it), and see what compromises I can make to meet my goals.

Thanks!

boggy 6th August 2011 12:31 PM

Quote:

Originally Posted by Philip Eno (Post 6911624)
Boggy,

Yes I think you understand what I'm trying to do. I'm trying to keep the place as homey as possible at the same time making it sound quite good. It's a home studio and it's (psychologically) important for me to rehearse with that kind of atmosphere.

I believe that we all understand what your needs are, but this isn't always easy to design. I think that we may try, at least. I have an idea about 2D binary diffuser (amplitude grating, LF transparent) built with your books...
Quote:

Originally Posted by Philip Eno (Post 6911624)
Right now, I'm trying to read up on acoustics (I'm completely ignorant about it), and see what compromises I can make to meet my goals.

That's good decision, before you start to throw your money in acoustic treatment, try to inform yourself.
Quote:

Originally Posted by Philip Eno (Post 6911624)
Thanks!

You're welcome. heh