On the diagram it states "+3dB at 3183Hz, shelving at 10610 Hz, Max at 20kHz.kozikowski wrote:The only defined points I know about are from the web site at 1061, 3183, and 20000

With the "shelf Eq" in Nyquist, the "frequency" is around the half way point between where the slope begins to deviate from the original level and where it plateaus out. So we are looking for a point between 3183 and 10610.

I set the default gain to -9.6dB but on looking again I think it should be -9.49

The figure of 4000 and the slope of 0.7 produce a curve that look pretty close to that in the graph (when used with a +ve gain).

Not very scientific, but I was just aiming for something in the right ball park

(got to leave you some opportunity to play ).

A bit of manual tweaking should quickly find the best sounding results.

Tweaking Hints:

Increasing the frequency will push the entire curve to the right (x-axis = frequency)

Reducing the slope will make the transition from gain=0 to gain=-9.49 more gradual (flatter curve) so the start of the curve will be at a lower frequency and the end of the curve at a higher frequency.

A high value for the slope (greater than 1) will produce an abrupt jump from the original level (just below the set frequency) to the -9.45dB level (just above the set frequency).