JWL's studio design

closer, wow thanks! I did a quick 2D sketch in OpenOffice Draw of the rear elevation. HOpefully that helps you to see it.

since you're making the wall so deep, maybe consider building that back wall as a complete diffuser setup - nesting several sets of 7 prime QRD? you could make some of the faces reversible for more absorption. this design is calculated to work on ~50hz through 2500hz.

Hi gullfo I thought about diffusion on the back wall. I was hesitant to add it at all (philosophically, absorption on the back wall makes more sense to me). I like the idea of lots of thick absorption in the rear of the room. The soffits and the angled slot resonators will be sending lots of sound that way. Absorption just makes sense to me. But, I think doing the entire wall would deaden it too much. So I decided to add some small diffusors to mix it up some. I like the new Realtraps diffusor, in that it combines diffusion at appropriate frequencies, and absorption in places where the diffusion doesn't work. But they are quite expensive; not sure I'll be able to afford them. If not, I'll likely just build my own. So yeah. I really like the idea of thick cotton absorbers. I have some cotton in my present studio; I really like it but I need more. This will give me that.

I've played a bit with Sketchup. I've figured out how to make the diffusors/shelves the size I had in mind, but I'm now trying to work out the quickest way to draw more absorbers stacked above and below. Once I figure that out, I'll post it here. I'll also try to start adding more detail. Thanks again for setting that up for me, kendale.... :)

OK, still trying to figure out Sketchup. I've cleaned up some of the lines, erased some redundant stuff, and gotten the absorbers the right size. I still need to draw in the 16" cotton batts laid horizontally above, below, and between the diffusor/shelves....

this design is calculated to work on ~50hz through 2500hz.

Gulfo maybe you meant 500 Hz and not 50 Hz, no way a diffuser works on that range unless it is really really huge

this design is calculated to work on ~50hz through 2500hz.

Gulfo maybe you meant 500 Hz and not 50 Hz, no way a diffuser works on that range unless it is really really huge Gateway mastering has a big diffuser http://www.rpginc.com/proaudio/projects/gateway.htm Nice interview with Bob Ludwig http://www.rpginc.com/news/interview4.htm

Andre, What's this in your signature ????? http://www.winmoneyonbets.com - a safe way to win money betting online ! Not very scientific like for an acoustic consultant, no?

i did mean 50hz. the one shown here is about ~12' wide or so... its based on a series of QRD prime 7 diffusers embedded. if you wanted to go a bit more you could add in the RPG diffusor board which adds a QRD prime 7 which acts on higher frequencies as well. and you could add upper and lower absoption (effectively the upper and lower wall-ceiling and wall-floor corners) since its design is ~6' high so it can be positioned up on the wall.

the low frequency limit to create an 50 Hz diffuser would be 1.7 m of depth walls.... Eric I removed that site from my signature but yes it is my site.

Interesting stuff, Andre. I don't know much about diffusors, especially the specific mechanics of them. Based on what I've heard from diffusion, I think it will be most useful to me from the midrange on up in my small room. Hopefully, if I do it right, it will create a nice sense of spaciousness that sounds different from just pure broadband absorption. The way I've designed my room, the corner absorbers will be 24"x24"x8' square "columns", with more horizontal "columns" of 16"x24"x8' at the wall/ceiling and wall/floor corners. The diffusors are between those, with small amounts of additional absorption between them. I'm trying to imagine what this room, as I've designed it, will sound like. Has anyone heard a room similar to this? Did you like it? Obviously, this is a subjective taste thing, but I'm very interested in opinions....

andrebrito wrote:

the low frequency limit to create an 50 Hz diffuser would be 1.7 m of depth walls....

if the period of the large diffuser was small, then the well depth would be the determining factor, but the overall width gives the wavelength period... the depth is secondary as is each well width.

jwl wrote:

I'm trying to imagine what this room, as I've designed it, will sound like. Has anyone heard a room similar to this? Did you like it?

one of the local studios (Lodi NJ) had (closed a couple of years ago) a wall with 4 RPG diffusers and built-in absorbers on the back of the CR and it sounded very "clean" - no weird deadness but no slap-back either - good balance overall. the room depth was about 18'.

Good to hear, Glenn. :-) Hopefully mine will sound good as well.....

Gulfo, Depth of those wells controls the low frequency limit of a QRD diffuser and the well width controls the upper limit frequency. You cannot diffuse low frequencies unless you have a "monster" diffuser

if the period of the large diffuser was small, then the well depth would be the determining factor, but the overall width gives the wavelength period... the depth is secondary as is each well width.

QRD with smaller periods (N=7 for instance) have better lower frequency distribution then the ones with higher periods

andrebrito wrote:

QRD with smaller periods (N=7 for instance) have better lower frequency distribution then the ones with higher periods

agreed. hence the prime 7 design... :-)

OK, I need some sketchup help. I got one of the horizontal absorbers drawn to the right size. I tried to copy and paste them several times (5 or 6 above and below the diffusor/shelves) but I couldn't get sketchup to play well with others. Can anyone help? I've attached the .skp file. I'd also attach a png, but for some reason it didn't export correctly and I don't want to reboot into windows at the moment. **EDIT. Corrupted attachment deleted. See below for the most up-to-date version.

its not coming up as a sketchup file... just some ideas - grouping is your friend and avoids things like erasing needed lines etc as well as making it easier to line up with other objects... if you are making multiple clones and they won't change, except all together, make it a component instead so updates to one affect all of them. please re-attach the sketch up file...

Strange. Not sure what's up with that. I'm sending this from my Windows partition. I'm going to go ahead and upload a png as well, even though it's too wide. Once it's uploaded, I'll resize it.... This is yet another reason why I hate Windows.... too much hassle. Linux is just simpler. Rant over. :evil: :evil: :wink: Thanks gullfo

like this? by double-clicking on the surface it selects the surface and the boundary lines. then holding shift - select the remaining 3 sides of the "absorber" and group it. then hold control-left-click+drag to clone it.

Regarding grouping: I figured out how to copy the absorber. But when I tried to paste it, it kept aligning up in the wrong place. I couldn't grok how to get it to just simply place 5 copies below the original. I'll look into grouping. Perhaps I should draw an absorber well away from everything else, make a grouping of 6 of them, and then move the group into place. Sound reasonable?

Wow, thanks gullfo. That's nearly there. The absorbers are flush with the rear wall, though, to give the back wall some depth and make it look less boxy (still pretty boxy though, LOL). Next time I go into windows I should be able to fix that. There will be panels covering all the cotton, btw. I'm debating whether I want to use normal cloth panels, or get large 2x4 auralex panels and use that to cover it. I'm leaning toward cloth, just on aesthetics alone.

i create "absorbers" off to one side of the drawing - maybe 2" x 2' x 4', or 4" thick etc... to make it a "standard size", group it and, then use ctrl, left-click+drag to put it in about the right position, then use the move tool to final position it. i do have some components made but its very fast to just draw and drag it and paste in the material i mostly just draw them. as far as grouping, typically I build the room - group it - sometimes lock it, build my inner walls, group it, build treatments - group and clone as needed. then i can go back and edit each group with doors and windows etc... this way lines and surfaces don't interact in unexpected ways...

jwl wrote:

There will be panels covering all the cotton, btw. I'm debating whether I want to use normal cloth panels, or get large 2x4 auralex panels and use that to cover it. I'm leaning toward cloth, just on aesthetics alone.

yeah, i'd go with the cloth as well.