I started with the trial but was soon converted as the program is easy to learn. (unlike other 3D progs I've tried) so I had to buy it - (around USD$470.00)
It allows you to draw totally in 3D to 1/8" accuracy. Changed my life

Anyway I've recently designed a couple of rooms for a friend in town and as he's not a client I can post the design for all to view. It's your typical basement with a low ceiling and cross beams etc. I'm still working on it so it'll probably change but it will give you an idea of how to construct one of these typical basement type studios, build soffits and resonators etc.
It shows the construction in a way that a 2D drawing can't.
The link to the file is here
http://johnlsayers.com/Stuff/Paddy2.skp
BTW - with the viewer you can look through the different pages where I've hidden layers or you can go to "View/Tourguide/slideshow" and it will play them in an animated sequence.
To move around:
Hold down scroll wheel and move mouse allows you to orbit around the model.
Hold down shift with the above allows you to pan left right.
Scroll wheel allows zoom in and out.
It takes a bit of practice but soon you'll be flying around the model

enjoy

cheers
John