Visualize equalizer

[DrLex]

Is there any way to draw a curve of what the frequency response of a parametric equalizer setting is? Of course, the coolest thing would be if rockbox itself could plot such a curve, as an extra option in the equalizer menu. Even cooler would be if it would be drawn in real-time while adjusting the parameters, but there's not enough space on the tiny screens of most players for this.
I would be happy already if I could experiment with some values 'offline', in some program that draws the curve for a certain set of parameters. It's pretty obvious how the 'gain' and 'frequency' parameters affect the curve, but it's hard to get a feeling for the 'Q' parameter.

[Chronon]

If you imagine a (Lorentzian) peak, Q is proportional to the frequency of the peak divided by the (band)width of the peak.  Roughly speaking it gives a measure of how sharp the peak is.  Higher Q means a narrower peak.  So, you'll be providing gain to a narrower range of frequencies if you use higher Q.  

I would guess someone in the audio business can probably point you to a proper program for calculating the resulting gain curve.  That's a bit out of my element, unfortunately.

[Febs]

DrLex, you might be interested in this thread from last year:

http://forums.rockbox.org/index.php?topic=5279.0

[Multiplex]

If you do a search for "musicdsp" in the forums (possibly in the thread Febs gives the link to) I posted a link to an Excel spreadsheet that does what you ask.

Somewhere in the wiki there is a description of the equealiser and its implementation which is where I got to the musicdsp site from and lurking round there I found the spreadsheet.

[DrLex]

DrLex, you might be interested in this thread from last year:

http://forums.rockbox.org/index.php?topic=5279.0

Thanks! I did search for "equalizer curve" in the forums, but this didn't return any results (now it only returns this thread).
That excel sheet is indeed what I was looking for, although I would have to hack into it to get the same configuration as the rockbox equalizer.
Is there any progress in the implementation of the 'advanced' equalizer UI? Or, how about a plugin that just draws the curve based on current EQ settings?