Thanks for the links.. it looks like that free tone generator only creates tones.. what I did (and what empeg did for the AutoEQ files) was create pink noise, then filter out all frequencies except for the targeted ones. So, the test file for the 50Hz band actually covers 20Hz to half way to the next band. You don't want just 50Hz.

Here is what JohnG emailed me:

Quote:
A reasonable estimate for the cutoffs would be would be the geometrical mean given by

Fcutoff = sqrt( Fcentre_high * Fcentre_low )

So between the 50 and 100 Hz bands you get 70.7Hz as the cutoff.

To make the tones I generated pink noise and applied FFT filter to pick out bands. Out of band freqnecies were set to 0% and in-band were set to 100%. To avoid ringing I sloped the walls of the filter to create transition regions of about 1/5 the width of the band.

There are some other steps to take too... you want to make sure all the tones have the same SPL (normalizing won't help). "WaveGain" is a good free program to do that...

I'm going to include a little tutorial, based on the very helpful emails from JohnG, on how to make your own test files..