This has been discussed before.

The microphone input on the Empeg can't sample at a high enough frequency to EQ the upper part of the range. I don't remember the exact number, but I think you could only get valid data up to 11k or 13k or something like that. You could theoretically extrapolate, though, based on the rest of the curve.

The empeg folks probably won't be developing this any time soon, but there's nothing to stop you from writing it yourself. Wanna be the first?

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Tony Fabris