Plotting filters frequency response

Hello,

First, I'd like to apologize if this post isn't on the right section of the forum. Since we are using SigmaDSP on our product and I couldn't find a sub-forum that would fit this question best, I posted it here. Before that I tried to contact some people via private message, but seems that it has been deactivated?

We have been developing a car audio processor that features Xovers, parametric EQs, etc. Everything is working beautifully, including all the formulas that gerenate the coefficients for the filters that are passed onto the DSP for processing.

However, I still couldn't find a solution to display these filters frequency respose, especially the Peaking EQ, which would provide a very useful visual feedback for the user. Every competitor has that, like this one:

What I've been looking for without success, is a way to plot the filter's frequency response, ESPECIALLY the Peaking EQ. I've been doing numerous tests, for example, I tried to plot the Peaking EQ by the center frequency, gain and bandwidth relation, but never got close enough to the real frequency response that I can see on the RTA measurement. I was hoping I could find a formula that I can use to find the points to plot. Since I haven't had sucess trying to find it, I created this post hoping that someone here can give me a point to start.

Any help will be greatly appreciated!

Thank you.