I've tried the free sketch-up, it sucks! With no dimensions, how do you know what you are drawing?
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.
I am dreaming of a concave curved speaker/end wall
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.