RTA - Alternatively if you are really into this, you can buy RTA software
for PC's and with a mike do the testing yourself. www.trueaudio.com has
RTA
software 99$ for 32 band rta.

If you know of other software, I'd like to know.


Thanks for the suggestion! Even free TrueRTA Level 0 seems useful enough for
my purposes. I also found out I can hear tones down to ~30hz and up to
15.8khz... although the 15khz whine makes me dizzy
The only thing I'm missing is background noise subtraction.

BTW Winamp could serve as real-time spectrum analyzer as well, although
without all the bells & whistles TrueRTA has.

Peter