I assume that the firm Tom is talking about is the company I work for dB Audio & Video. We have (as far as we know) the only portable VRAS system in the world. We can set it up in a couple of hours. It takes the VRAS guys a day or two to set up a demo. The VRAS (LCS) is probably the most realistic system out there. It does not use time variance in which you can hear the tails moving around if you listen carefully. The demo we have would make a great recording room.
The knock off we sometimes use (when budget is a problem) is a system that I came up with and works very well. It can do several things the VRAS cannot. I am not trying to fool Europian acousticians (just a bunch of Southern Baptists-HAHA). We have used my system to "copy" the sound of the large sanctuary into the choir room, so the choir feels like they are signing in the main room.
I will say this-there is a learning curve and I am still very much in it (as far as things you should and should not do). But I am getting better all the time.
One of the biggest things about using a variable rooms system is the room itself. It needs to be very dry (RT60 around .5-.7 Sec) and totally free of flutter echo. This is great for speech, but really allows the system to work to its full potential when doing choral or classical or organ music. It is not cheap to do right, but the results are worth it.
It is my belief that in a few years most venues will be using a system of some sort, when the operators realize that the rooms can have "perfect acoustics" for a variety of types of performances. Right now the term perfect acoustics applies to one type of performance-what is perfect for speech is lousy for an organ and vice versa. In the future you will be able to have a conferance during the day and an organ recital at night and every body will be happy, and the owner has now put paying seats in his venue twice in a single day. When this starts to happen, the "high" price tag will seem small in a very short time period.
Ivan Beaver
dB Audio and Video