Paragraphic EQ?

stefan · 4 May 2005

Tom7777 wrote: Is this possible with SM? im guessing maybe it can be done using DSP but i can't really code at the moment. It would split any incoming audio into 4 frequency/bands with 1 for bass and 4 for hats/snares ect im sure you know what i mean. Thanks

Well, yes it is. You can just use lowpass and highpass filters.

What is a paragraphic EQ? All you want is a bandsplitter, right? 🙂

Tom7777 · 4 May 2005

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stefan · 4 May 2005

Tom7777 wrote: Like this - http://www.waves.com/content.asp?id=161

Filters are kind of a work around method i would say, 10 bands is what i want which can be raised or lowered, they also have a curve/slope type option.

Ok, paragraphic = graphical parametric eq. Making a parametric eq isn't that hard in the code component, if you're a coder. But afaik, you aren't, so it'd be tricker for you 🙂 Anyways, atm I'm too busy, but I will implement EQ stuff later on, then you can use as many bands as you like... 🙂

Tom7777 · 4 May 2005

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stefan · 4 May 2005

As far as I can see, that code will just output silence. Mainly due to this: bnd1 = b1 * f1 * a1;

b1 is zero, you never set b1 to anything.

apart from that, there's no filters in your code. also you override the amp inputs by setting them to 0.25 in the code.

Tom7777 · 4 May 2005

Ok as i though my guess was bad. I think i will wait for your version 🙂

Shifrin · 4 May 2005

You could try to implement the RBJ CookBook parametric filters in the code component, I've not tried myself yet but I'd guess it'd doable (or will be soon).

It's also possible to draw a graph of the filters frequency response on you GUI, the harder part might be implementing draggable nodes. Well, I'm sure it can all be done if not now then soon. Maybe I'll get around to trying one myself at some point 🙂

Shif.

Tom7777 · 4 May 2005

Is z^-1 (pow) possible with the coding module? They seem to use pow a lot in the parametric filters.

stefan · 4 May 2005

Tom7777 wrote: Is z^-1 (pow) possible with the coding module? They seem to use pow a lot in the parametric filters.

z^-1 isn't really your normal pow (well, it is, but in the z-plane). z^-1 = one sample delay, which you easily can do in the code module.

polyin in; polyout out; float lastIn;

out = lastIn; lastIn = in;

that's a z^-1.

Tom7777 · 4 May 2005

Thanks stefancrs, that Z^-1 pow code helps a lot. 🙂 Much more simple than i thought it would be.

stefan · 4 May 2005

Tom7777 wrote: Thanks stefancrs, that Z^-1 pow code helps a lot. 🙂 Much more simple than i thought it would be.

you could just use the 1 sample delay component as well 🙂

Tom7777 · 4 May 2005

yeah i know i have been up until now, but this will help for if i try to make dsp code that has the pow or Z^-1 within its code.

unkargherth · 4 May 2005

Shifrin wrote: You could try to implement the RBJ CookBook parametric filters in the code component, I've not tried myself yet but I'd guess it'd doable (or will be soon).

I tried it and worked partially. Easy for LP , HP and Notch. Problems start when you try Band pass ( CSG or C0dB), EQ Peak and shelving filters. The lacking of Pow() adn SQRT funcs precludes to do it

Shifrin wrote: It's also possible to draw a graph of the filters frequency response on you GUI, the harder part might be implementing draggable nodes. Well, I'm sure it can all be done if not now then soon. Maybe I'll get around to trying one myself at some point 🙂 Shif.

Dragging points shopuld be fairly easy. Whats dificult is:

a) convert point position to filter coeffs b) Draw those nice curves

Anyway, there's no real need to code a new Filter. If you build a Filtercoeff equiv module that allows to select the filter type and gain/att added to standard cut and res. Formulas for low pass, Peak eq and Low shelf can be found here If somebody is clever enough to derive the formulas for BP, HP and Hi shelf, we can get a nice set of filters, that i suspect are stackable ( chain two of them with same params and you get double attenuation, without to much CPU hit)

Shifrin · 4 May 2005

unkargherth wrote: Problems start when you try Band pass ( CSG or C0dB), EQ Peak and shelving filters. The lacking of Pow() adn SQRT funcs precludes to do it

Indeed, I'm hoping these will be added to the code component, they'll help a *lot* with things like this!

unkargherth wrote: Dragging points shopuld be fairly easy. Whats dificult is:

a) convert point position to filter coeffs b) Draw those nice curves

That's kind of what I meant, hehe. It is straight forward to make a draggable node but the conversion into filter coeffs might be a little harder. I believe you can already draw the curves by passing an impulse through the filter, performing fft, then drawing the graph. Although maybe I got confused - I get confused a lot 😉

Shif.