Anechoic chamber availability and advice

["Maher, Rob" <rmaher@xxxxxxxxxxxxxxx>]

Greetings--

I am in need of some anechoic measurements for an experimental microphone
array system.  Measurements down to 100 Hz would be desirable.  The size of
the array probably prevents TDS or similar DSP techniques to simulate
anechoic conditions, so I would appreciate any answers or suggestions
related to the following questions:

(1) Are there any of you (U.S. or Canada) who have an anechoic chamber with
a liberal access policy (e.g., no cost or low cost)?

(2) Has anyone been involved with the purchase or construction of a 100 Hz
anechoic chamber?  If so, can you state an order-of-magnitude budget?

(3) I have tried some preliminary measurements outdoors and in a large
lecture hall (with time gating).  Both methods are inconvenient and provided
somewhat dubious results.  Anyone have suggestions on such "big room"
quasi-anechoic techniques?

Thanks,
Rob Maher
Montana State University
rob.maher@montana.edu