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Vray or similar for reflection calculation? Effects Pedals, Units & Accessories
Old 24th December 2010
  #1
Lives for gear
Vray or similar for reflection calculation?

I'm looking at re-designing my control room, I have the whole room more or less dead right now and I'm thinking of using multiple angled surfaces to create a RFZ, in what otherwise will still be a fairly live/bright room (raw room is 20f x 10f x 8ft ceilings)

I know there is a name for this type of layout, I remember reading a BBC tech paper on it. . . But I don't remember it.

Anyway I'm sure there is a way to do this using a bunch of math that is way over my head, but I was wondering if Vray, with dispersion limited light polars (eg floodsish) and mirrors for reflective surfaces and black for absorbative ones would give a decent representation of a rooms HF or MF reflections? Especially if it were possible to block the direct light, and show only reflections?

Otherwise I'd love some feedback on the rough draft design. Thanks
Attached Thumbnails
Vray or similar for reflection calculation?-cr1.jpg   Vray or similar for reflection calculation?-cr2.jpg   Vray or similar for reflection calculation?-cr3.jpg  
Attached Files
File Type: skp CR messin.skp (3.00 MB, 136 views)
Old 25th December 2010
  #2
Gear Addict
 

Sounds plausible.
Old 25th December 2010
  #3
Gear Guru
 
Ethan Winer's Avatar
 

Lightbulb

Quote:
Originally Posted by RyanC View Post
I'm sure there is a way to do this using a bunch of math that is way over my head
Just make the side-wall angles at least 35 degrees and you should be good to go. But don't forget the ceiling reflections.

More on the 35 degree angle requirement here, from Wes Lachot:

Early Reflections

--Ethan

________________
The Acoustic Treatment Experts
Old 29th December 2010
  #4
Lives for gear
I'm messing with this-

It works great! Someone should seriously make an app like this specialized for audio. Even as it is you can pretty easily see the difference between 1st reflections and diffuse light. I don't know enough about how to tweak the different material settings for optimum results (eg mirror or shiny finishes should show a clear dot of the source light).

I'm just building a little box that has 100w x 60h dispersion like my LSR32's (supposedly have), but in my room given the narrower width and my preference to be a little further back then equilateral, 35 degree's is actually a bad angle because it would have L-R first reflections (the room would have to be wider, but it seems this would still be somewhat problematic). Wider angles (27 degrees or so) is looking MUCH better with the second tier of the absorptive side of the angled walls catching the L to R reflections.

Just so it makes sense, if you're looking at the pics there each tier would be reflective on the console facing side, and absorptive on the speaker facing side.
Old 29th December 2010
  #5
Gear Guru
Rays

You may be better off going straight to Sketchup. Ask John Dykstra. He has shown multiple ray traces right there in room models.
DD
Old 30th December 2010
  #6
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avare's Avatar
 

Quote:
Originally Posted by DanDan View Post
You may be better off going straight to Sketchup. Ask John Dykstra. He has shown multiple ray traces right there in room models.
+1. Just take the refecting boundary and use it as the reflecting line to make a mirror image of the listening area and areas significant to ISD are straightforward. If you want to get fancy, and it isn't, make the rays 16.5 or 22 feet longer than the speaker listener path and you have the time component covered too.

Andre
Old 30th December 2010
  #8
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Nordenstam's Avatar
 

Protractor tool in sketchup does what it says.
Old 31st December 2010
  #9
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jhbrandt's Avatar
Yep, I use AutoCAD. It's quite simple to see once it is drawn and adjustments are easily made.

Happy New Year!

Cheers,
John
Old 3rd January 2011
  #10
Lives for gear
Thanks-

Glen, awesome, that's exactly what I was looking for. Playing with this has made me realize that this traditional 2d CID design could maybe be made to have a much larger sweet spot by aiming reflections in 3 dimensions (EG side walls reflect up/down). I'm just starting to mess with this and I have to wait till I can borrow my buddies laptop with V-ray to do the renders, but it looks promising. Am I re-inventing the wheel here? Is there already a 3D CID?

3d reflections aren't handled so easily with the protractor tool no? Or am I missing something in sketchup? I figured out how to make mirrors in Vray, and it works quite well, there are little things here and there that I probably would have missed if I tried to run it all from the protractor. Not to mention I have no idea how to use the protractor for reflections in 3 dimensions.
Old 3rd January 2011
  #11
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gullfo's Avatar
 

in SketchUp it was pretty easy to model all of the CID designs using the BBC dimensions. not sure about vray. i think the challenge for CID is that the work doesn't seem complete somehow but many of the principles being explored there have some value overall. for ray tracing i mainly use the protractor tool.
Old 3rd January 2011
  #12
Lives for gear
Wow. . . I think I figured out what Hanson Hsu's ZR is.
Old 3rd January 2011
  #13
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avare's Avatar
 

Quote:
Originally Posted by RyanC View Post
Wow. . . I think I figured out what Hanson Hsu's ZR is.
Fill us in please!

Andre
Old 4th January 2011
  #14
Lives for gear
OK so how does intellectual property law work with this sort of thing? I couldn't get sued for sharing it here could I? I've never been in one of those rooms, or signed any NDA's or anything.

I'm almost 100% sure this is it. I'm looking at renders of a hall of mirrors (100% reflective) and a light with 180 HxV dispersion and so far there is not one place in the room you can see a reflection of the direct light. This is with 100% reflective surfaces (I tested with square and CID and in those you can clearly see the direct light reflections).

Otherwise I'm happy to share. . .
Old 4th January 2011
  #15
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andrebrito's Avatar
 

You can do this as an approach, I do it myself but in terms of modeling is wrong.

Reflections are much more complex than simple "light" reflections... this is a good method to extrapolate to more complex modeling tools
Old 4th January 2011
  #16
Lives for gear
This isn't light diffusing on a "painted" surface. All surfaces are mirrors when rendered. Mirrors will reflect the light source. I've tested it in the renders in Vray and it works.

Same concept as using real mirrors to find ER points in a real room.

I know light travels a whole lot faster then sound, but this is the only model I've made where the reflected light travels through so much atmosphere that it makes white light reflect off a white object with a blue tint. This is in a 200sf room BTW.
Old 4th January 2011
  #17
Lives for gear
Sorry guys. . . quiting smoking after 16 years and drinking is a bad combo.

I am still showing a reflection free room here.
Old 6th January 2011
  #18
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andrebrito's Avatar
 

Maybe I was not clear enough and I sound like an idiot.

When I meant wrong I mean inaccurate. Acoustical modeling software like
CATT is much more than just a "light" approach. What you do with Vray you can do it with paper and pencil... using SketchUp is a good option as well.
Old 6th January 2011
  #19
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avare's Avatar
 

Quote:
Originally Posted by RyanC View Post
OK so how does intellectual property law work with this sort of thing? I couldn't get sued for sharing it here could I? I've never been in one of those rooms, or signed any NDA's or anything.
Caution is good. Products are protected by patents. No patent, no protection. A Patent Pending means that a patent has been applied for, but has not been granted yet. IOW a patent MAY BE granted in the future, which would protect the product. I have not found a pending patent for this type of room in the US Patent and Trademark Office website.

There is no legal protection of any intellectual material involved with this control room design.

Andre
Old 9th January 2011
  #20
Lives for gear
Ok cool-

So here is what I'm thinking . . . each "rib" runs at a 45 degree angle floor to ceiling and the ribs themselves are 45 degree triangles. This would effectively reflect all the speakers horizontal dispersion in the vertical domain and vice versa, when those reflections hit the other walls, they get turned back into the other dimension again (away from the listening area).

For some reason Vray isn't working anymore. . . but it works, other then you can see floor reflections on the cieling with a 8ft cieling, but I'm thinking a console would easily block those (back to the floor where the listening position is). Or a little bit of absorption on the ribs.

My guess is that ZR would be all this hidden behind acoustically transparent fabric. Probably the angles of the ribs and triangles could be made to work better then just 45/45 but at the same time it is half way between 90 so it should reflect H to V and V to H as much as possible without going as far as calculating for fixed speaker placement.

I don't really know how to protract in 3d, but in Vray you can see that at least side to side there isn't one reflection in the listening position or even anywhere really side to side.

Again maybe I'm re-inventing the wheel here, if this is already an established design I'd love to read more about it.

No doubt this would not be easy to build. Thanks again-
Attached Thumbnails
Vray or similar for reflection calculation?-reflective-rfz.jpg  
Old 19th February 2011
  #21
Gear Head
 

Your attached image looks quite interesting....

I'm not an acoustics expert at all, so please correct me if I'm wrong. But, don't those "slats" act as diffusers or "angled reflectors" and will they not only be effective at certain frequencies? Would they not be minimally effective at lower frequencies? In other words at lower frequencies the slats are not really "present" and the sound waves will still reflect off at the same angles as if the slats were not there?

If I'm incorrect then I think your solution may not be that expensive to implement!
Old 19th February 2011
  #22
SAC
Registered User
 

Quote:
Originally Posted by RyanC View Post

Again maybe I'm re-inventing the wheel here, if this is already an established design I'd love to read more about it.

No doubt this would not be easy to build. -

First, ray theory, while handy for extremely basic imagineering, is far too simplistic to describe sound propagation.

Plus one is faced with a more basis issue, that of modeling the signal source. While its nice to assume that it is a monolithic controlled Q 'point source', the reality is anything but.

For starters, how does one account for variations in the nature of propagation and interaction based upon the wavelengths? Since when does the full spectrum of sound act as a collimated specular reflection?

Not only does one have a unit comprised of drivers where each may have different acoustical centers, they exist separately (non-co-located) in space, each with different power response/dispersion signatures, while they fail to distinguish between their near and far field responses - something that must be addressed in a small acoustical space.

And Then one gets to start addressing the loudspeaker's behavior in the room and the varieties of interaction with boundaries of various size, orientation, and acoustical impedance.

The wheel has indeed been invented. One might want to become aware of the point in the process where the currently available tools are situated, starting by reviewing programs like Phd, CATT-A and EASE...while remaining cognizant of their limitations.
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