# How to draw SPL curve for a parametric equalizer?

I want to show (graphically) the Gain/Attenuation vs frequency of a parametric equalizer.

This is my circuit:

https://sound-au.com/project28.htm

The same schematicas as a screenshot:

I want to show the effect of VR1 thru VR7 in the same way as it's shown in the Winamp:

• Instead of trying to plot the spectrum by formulas, you're much, much better off building the schematic in a SPICE simulator ans simulating with .AC. That's because the transfer function is very complex, but mostly any variation of the potentiometers will influence the outcome. A simulation will take care of these on the fly (and less error-prone). – a concerned citizen Mar 24 at 13:31