[Jerry Steiger]

"Scott Dorsey" wrote in message
...
Look at some of the room mode calculators on the web. If you can make it
large enough that all of the major room modes fall below the lowest
frequency of interest, that's a start.

When you say major, how high do I need to go? If it is just the first mode,
then about 2' will do at 300 Hz, but if I need to go the 9th mode, then we
are talking 16'.

Right, that's not the right tool for the job... look for the larger
chambers.
You can get away without a walk-in but you are going to need something
larger
than a fridge if you care about 300 Hz.

I can find space for something roughly refrigerator size .

I am thinking that Chris is correct, that if I get enough absorbtion at
the
frequencies of interst, I don't need to worry much about the modes in the
chamber or the resonances in the walls. But can I get enough absorbtion?

If you want absorption at 300 Hz, you need several feet of fibreglass.
And
yes, that is the solution.

OK, this sounds very promising. If I can get away with two feet of
fiberglass or cotton on all sides, then a 5'x5'x8' box would leave me with a
1'x1'x4' test space. Now all I need is a reasonably flexible way of mounting
and accessing the micrphones and speakers in the test area.

Thanks again!

Jerry Steiger