"The Flash" wrote in message
...
Uh, I used to test in a anechoic chamber at the local university but don't
now,

Most anechoic chambers are useless below 100 Hz as well.

I also tested other areas and found the following. You can test fine in
you living room. Background noiselevel is typically 5OdB at home. You
place
a mat of acoustic foam on the floor, put yout mics up (1m away) place 4
more
sheets of acoustic foam round the speaker and mic's and final sheet on top

These knock 10dB off background noise

Not at 20 Hz they don't.

and stop echo, run up 1 watt at 1khz
gives about 90dB in most case, this is 50dB above background

???.
50dB BG from 90 dB SPL gives 40 dB.

and you can run
a sweep test and get results the same as in an anechoic chamber.
Again I think this is all smoke and mirrors stuff so that its 'too hard'
to
do yourself.

Sure you can do that, and your measurement uncertainty is ?????

TonyP.