Sound modeling from AutoCAD 3D?

Discussion in 'Listening Spaces' started by VolvoHeretic, Sep 21, 2011.

  1. VolvoHeretic

    VolvoHeretic Well-Known Member

    I can 3D model my entire house in AutoCAD down to the nearest 1/8". If so, can you highly trained sound engineers calculate where I should sit to avoid all of the nodes and voids and where to place my speakers and how to set my EQ? :)
     
  2. RevMen

    RevMen The Reverend Menacer

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    How about Sketchup? Prettier, faster, free.

    I have a mostly-built Sketchup model of my room. I keep meaning to post it.
     
  3. tchuck

    tchuck Super Member

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    Comparing Sketchup to AutoCAD is like comparing a radio flyer to a Unimog. Sketchup is absolutely primitive by comparison. To be honest it's pretty primitive by any measure. Even still AutoCAD is for A&E, not sound modeling. I think you could accomplish your goals with a way simpler program designed specifically for sound modeling.
     
  4. RevMen

    RevMen The Reverend Menacer

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    More complicated != better

    Sketchup is free, intuitive, and has exactly the right level of detail for modeling a listening room. Most of us don't have AutoCAD, so an AutoCAD drawing won't be very useful.

    I am not aware of any "way simpler" programs designed for sound modeling. If you're thinking of EASE or ODEON, I think you'll be disappointed because they are really not that simple to use.
     
  5. VolvoHeretic

    VolvoHeretic Well-Known Member

    I've tried the free sketch-up, it sucks! With no dimensions, how do you know what you are drawing? I am dreaming of a concave curved speaker/end wall with the speakers aimed at the listing position at 30 degrees angle to perpendicular so the curve starting on a 14' wall would be something like this.

    [​IMG]
     
  6. tchuck

    tchuck Super Member

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    What you said about Sketchup is correct, but none of that will help the OP with analyzing his listening room. If you want to see in cartoonish colors what your room will look like with a chair in the middle and speakers against a wall then it's perfect, but I don't think that is the goal here.

    I meant "way simpler" than AutoCAD, which is a professional grade architecture and engineering tool for use by professionals. It has no sound engineering accommodations and is equally (un)suitable for that task.

    I'm not familiar at all with sound wave analysis software so i couldn't say which will be up to the task. That's not my point anyway. My point is that AutoCAD isn't the right tool, and if AutoCAD isn't, Sketchup certainly isn't. In the real world Sketchup is used by interior designers to visualize furniture placement. No one who builds anything important uses it for anything beyond a digital sketchpad...which is it's intended use.
     
  7. tchuck

    tchuck Super Member

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    You're on the right track, but you'll need to find someone with some sound analysis software, preferably someone who really knows how to use it, and find out what they need from you in terms of a file format. If there's a way for them to import a model, chances are good that AutoCAD can export the right format.
     
  8. VolvoHeretic

    VolvoHeretic Well-Known Member

    I know what you mean Tchuck, I have been looking for someone with a virtual windtunnel to import this thing and tell me if if will stick like glue at 250mph or flip over backwards. :) They are hard to find for free.

    [​IMG]
     
  9. tchuck

    tchuck Super Member

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    Whoa. That's a big project... Why the four wheels in the front?
     
  10. VolvoHeretic

    VolvoHeretic Well-Known Member

    The four tandom 8x17 wheels in front are to match the four dually 9x17 wheels in back and let me enter corners without slowing down on street tires. :)
     
  11. tchuck

    tchuck Super Member

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    Well, you're definitely not lacking in ambition. Good luck, man. :thmbsp:
     
  12. melofelo

    melofelo Addicted Member

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    design the underside surface of the car like an upside down aerofoil...and lower the side panels so they almost touch the ground...
    think Lotus 78 or Lotus 79 John Player Special... :D
    it should drive upside down on the roof of a tunnel once you hit about 140 mph ..:thmbsp:
     
  13. VolvoHeretic

    VolvoHeretic Well-Known Member

    It already has a belly venturi and will have rubber belting on the sides like my Volvo 1800.

    [​IMG]

    [​IMG]
     
    Last edited: Sep 22, 2011
  14. tomlinmgt

    tomlinmgt Lunatic Member

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    Why no front air dam or diffuser to help the ground effect side skirts? And just looking at those Radial T/A's with the intended purpose of high speed handling makes my a**hole pucker! Good Lord, tire compound technology sure has come a LONG way since then. Throw some teeth in the grill and you'd be straight out of Death Race 2000! What were we talking about?
     
  15. VolvoHeretic

    VolvoHeretic Well-Known Member

    Back in the '70's those TA's were as good as it got. :) Unfortunately, as tire technology advanced, they never supported the 15" wheel size. And it's got an air dam, able to punt small animals and children harmlessly out of the way.

    A vitual sound room should be easily able to see a 3d room, but maybe it still needs the power of a super computer to do the math like a CFD vitual wind tunnel program.

    [​IMG]
     
    Last edited: Sep 22, 2011
  16. RevMen

    RevMen The Reverend Menacer

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    That's an odd thing to say. Why do you think there are no dimensions?

    Sketchup is better than you guys are giving it credit for. It's absolutely not a replacement for AutoCAD or Revit and it doesn't pretend to be. You have to think in 3 dimensions, and you have to think about the level of detail that's useful for modeling a listening space. I'm not talking about modeling in the sense that it performs an acoustical analysis, only in the sense that it allows you to convey the physical realities of your listening space to others perfectly.

    But that doesn't mean that it will never be able to do acoustics analysis. Do a search for ray-tracing plugins and you might find yourself surprised at its spacial modeling capabilities. I've not found an acoustic ray-trace plugin, but that just means no one has written one yet. The ability to assign material properties to surfaces is built in and it uses Ruby to run scripts, which is the most user-friendly language known to man. Writing an acoustic ray-trace plugin will be far, far easier than writing a LISP routine to accomplish the same thing in AutoCAD.

    Actually, now that I think about it, there is a new sketchup-based product on the market for outdoor noise analysis called Olive Tree Lab. The author posted the beta version in an acoustics group on Linked-In and I tried it out a few months ago. It seemed promising. It was a little rough, but I think he's made some refinements since then (and started charging for it). That software isn't useful for audiophiles, since our problems are single room, indoor, but it illustrates very nicely that Sketchup can be an excellent platform for acoustical analysis.

    Unless your goal is to concentrate sound to a specific point in space, stay very far away from concave curved surfaces. Curved mirrors work just as well for sound as they do for EMR.

    I guess it would be cool for a mono system, but this would absolutely wreck a stereo image. It'd sure be loud, though!

    Here's me in Seattle in front of the children's museum. They have a set of "whisper dishes" set up, which are a blast to play with. There's a little iron ring on each dish which shows you where the focal point is. One person stands at each dish with their heads near the rings and you can hear each other whispering clearly across the courtyard.

    [​IMG]
     
  17. tomlinmgt

    tomlinmgt Lunatic Member

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    And a big chrome bumper to blind 'em right before they get relocated!
    No doubt, canyon carving' in the 70's on street tires was very, um...harcore. I gotta know, were you pumpin any tunes during those twisty two-lane assaults and if so, what/who put in the zone? Sorry I'm off topic guys, but this is pretty radical stuff for a car guy. I gotta' ask.
     
  18. VolvoHeretic

    VolvoHeretic Well-Known Member

    Ok, no concave walls.:sigh: I was just thinking of how great the little fiberglass round dome house a friend rented and how the accustics in there sounded with a little stereo back in the '70's.:yes: I guess I can't remember how Sketch worked except that I couldn't do anything with it, and wondered how people were drawing such unbelievably good car drawings with it

    That car is so loud that you couldn't hear the 7 watt cassette deck anyways, but it was Led Zepplin and Pink Floyd.
     
    Last edited: Sep 22, 2011
  19. tomlinmgt

    tomlinmgt Lunatic Member

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    A casette deck in your car in the 70's. You must've gotten all the chicks with that thing! Too cool, man....too cool.
     
  20. tchuck

    tchuck Super Member

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    I may be slightly underselling Sketchup, but on the same token I think you're downplaying the realities of engineering analysis.

    Think in three dimensions? AutoCAD and Revit are both extremely capable 3D modeling applications. I think it's safe to say we're all thinking in three dimensions here. You keep referring to "modeling" a listening room, but if you read the first post of this thread you will realize that what the OP is actually looking for is analysis, not modeling. In post #5 you can see that he has already modeled his room in AutoCAD. How can Sketchup possibly improve upon what he has already done? Sketchup's forte is rendering, and even in that tiny area ACAD is far superior.

    "Never" is a powerful term. I'm not saying Sketchup will never be able to do acoustic analysis, I'm saying it can't do it right now. The OP isn't trying to analyze some hypothetical room at some infinite point in the future. He's trying to do it with an existing design right now.
    Analysis with a LISP routine? I've written a lot of LISP routines for myriad situations and the idea of performing acoustic analysis with one is ridiculous to me. I'm not saying it's impossible, but way, WAY outside anything I've ever seen done with LISP.

    That Olive Tree Labs software is a stand alone acoustic analysis application, not Sketchup. Saying it's a "sketchup based product" is like saying an F1 engine is a "Model-T based product". On the most basic level perhaps, but not even close really. If you look at this LINK you will see exactly what separates the two programs in terms of acoustic capabilities. In Terrain you specify the actual physical properties of materials. In Sketchup you specify only the visual properties.
     

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