4 Band EQ: how to made?

shama's icon

Hello, i'm new user of Max MSP.

I'm trying to make a 4 band parametric EQ but i'm not able to do it.

I find and watch che object filtergraph with cascade method but i don't understand how i have to use for my 4 band eq.

I want made an eq with parametres changed by knob (like an hardware eq [but with graphic rappresentation]) or by mouse modifing che values in graph (like a software eq [eq in logic, pro tools, etc..] ).

If you could help me I would be grateful because I don't understand...

ps. sorry for my bad english in post

Holland Hopson's icon

Here's a start using cascade~.

Max Patch
Copy patch and select New From Clipboard in Max.

Luke Hall's icon

You will probably want to use peaknotch rather than bandpass filters for the middle two [filtergraph~]s. This can be changed from the object inspector.

lh

shama's icon

Holland Hopson wrote on Tue, 21 April 2009 20:15Here's a start using cascade~.

what you mean?

I don't understand how to make the 4 band... 1 band (1 filter [bandpass, lowshelf, peak etc] it's ok, but i don't understand how to make 4 band.

I read the cascade~ object and biquad~ object but i don't understand very well how them working, above all the biquad~ object...

Thanks a lot

Roman Thilenius's icon

in case you wonder how to use the filtergraph for more that one biquad, this is not possible. you can only use it for displaying a curve of more than one set of coefficients.
if you are building a fixed frequency eq you can easily use a transparent pictslider object for Q and gain by putting it over the filtergraph, if you build a normal eq this is too difficult and your best bet are additional sliders and knobs beside the graph.

shama's icon

Roman Thilenius wrote on Wed, 22 April 2009 07:53
in case you wonder how to use the filtergraph for more that one biquad, this is not possible. you can only use it for displaying a curve of more than one set of coefficients.
if you are building a fixed frequency eq you can easily use a transparent pictslider object for Q and gain by putting it over the filtergraph, if you build a normal eq this is too difficult and your best bet are additional sliders and knobs beside the graph.

I want to make a parametric eq, not with fixed frequency.
i don't understand the object [biquad] and how i can use the pictslider over the filtergraph.

An example' patch of 4 band eq is not possible to find or see on the internet? I want to study how to male this eq, is not for commercial-work or similar... only personal study

Holland Hopson's icon

Shama,
Here's an expanded version of the patch I posted previously. I've included another UI approach using the nfilters message to filtergraph~. Hope this helps.

Max Patch
Copy patch and select New From Clipboard in Max.

Roman Thilenius's icon

shama wrote on Wed, 22 April 2009 22:43
I want to make a parametric eq, not with fixed frequency.
i don't understand the object [biquad] and how i can use the pictslider over the filtergraph.

biquad~ IS a difficult object, but still better than FIR filters based on transfer functions, because you have to program those yourself.

i attach a simple EQ of mine.
it has 3 bands, and uses the filtergraph object to calculate the coefficients for biquad. then it displays the result of all three filters in another filtergraph. typically setup will put filters in a series, then disallow crossing the freqeuncy settings. sometimes
parallel biqads also make sense.

if you want to add Q control you will find out yourself
how it works, just look how i did it for the frequency.

this patch is not perfect but probably better for you than the biquad helpfile.

-110

shama's icon

Many thanks at all, i make this eq, i'm testing it now!

I help myself with che tutorial "guitar processing", where there's an eq!

Roman Thilenius, your eq is beautiful but it's complicated for my to understand... many objects i don't know well..

Tj Shredder's icon

You would want to use cascade~ not biquad, or look into svf~
This is for studying:

Max Patch
Copy patch and select New From Clipboard in Max.

roger.carruthers's icon

Roman,
the 110.OLS-i-3 abstraction is missing. Love the Koblo look, btw,
cheers
Roger

Roman Thilenius's icon

roger.carruthers wrote on Mon, 27 April 2009 12:01Roman,
the 110.OLS-i-3 abstraction is missing. Love the Koblo look, btw,
cheers
Roger

oops..

you probably also noticed that this -25 +25 seems somehow wrong... and yes, it is.

i bought some webspace yesterday so i can re-up the 2007 collection soon.

-110

bob76's icon

all that mass of long text - how do I get that into max to look like a patch?

Chris Muir's icon
bob76's icon

thanks - sorry, common posting, but couldn't find it. All works, cheers!