Put my settings down to experience, guesstimate and trial & error. I studied electronics and worked as a sound tech at university, so that gave me a starting point.

Q factor is defined as f/bandwidth, where the bandwidth is delimited by the -3dB points. So if you're adding +3db, you'll get a 2nd order parametric curve that ranges from 0dB gain at f-(BW/2) to +3dB at f and back down to 0dB at f+(BW/2)

With my suggested values, that means the -3dB points should be -150Hz and 350Hz for the bass, and -40KHz and 60KHz for the treble, which looks really wrong, but certainly doesn't sound that wrong. I'm getting more convinced that there is a bug in the player's eq code. The fact that the Q defaults to 0.55 is strange...

Anyway I'm still looking into these values and the player behaviour. It'll be interesting to see what the consensus is on the best values to use. I wouldn't push bass below 75 or above 200, likewise 6KHz and 12KHz for treble.

I'm going to have to download a white noise file to my empeg and dig out that FFT program on my laptop soon...