Forums > MaxMSP

### Building a filter envelope for filtergraph~ ??

Dec 24 2008 | 10:46 am

Is this possible? Cant work out how you’d do it.

Any tips or some code would be greatly appreciated!

Cheers,
J.
(P.S happy christmas eve :o)

Dec 24 2008 | 3:00 pm

you can use it in conjunction with cascade~ or biquad~ i think. is that what you mean? have a look at the cascade~ helpfile

Dec 24 2008 | 4:26 pm

On 12/24/08 4:47 AM, "James" wrote:

>
>
> Is this possible? Cant work out how you’d do it.

[function], [lines], and a few patch cords should do the trick…

Dec 24 2008 | 5:07 pm

If it’s a lowpass filter, check into lores~. You could also use
filtercoeff~ to control biquad~. It’s like filtergraph~ but works at signal
rate. Check the docs for how to use it.

Since you know that adsr~ is outputting a 0-1 envelope, you could do a
little math on that…

from frequency going into cycle
|
|
*~ 16 (this would place your cutoff four octaves above your fundamental,
for example)
|
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*~ signal coming out of adsr~
|
into freq. cutoff for your filter.

Now you have a filter that changes in relationship to the frequency of your
fundamental. (probably more userful than a static frequency)

thanks,.
Peter McCulloch

On Wed, Dec 24, 2008 at 10:26 AM, Brennon Bortz wrote:

> On 12/24/08 4:47 AM, "James" wrote:
>
> >
> >
> > Is this possible? Cant work out how you’d do it.
>
> [function], [lines], and a few patch cords should do the trick…
>
>
>

Dec 24 2008 | 7:12 pm

Actually, this would work a little better:

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*~ 12.
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+~ 4.
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*~ frequency of synth fundamental
|
to filter cutoff

Sweeps a maximum of four octaves above to two octaves above. (Adjust values
as needed)

Peter McCulloch

Dec 25 2008 | 6:09 pm

Attempting to create a filter envelope for a filtergraph was the my first real project that helped me learn max a a month or so ago. In the end it was much easier then I thought it would be (with a little help from the forums). First off, I found a problem trying to create the envelope on the filtergraph itself because in essence, the filtergraph just generates input for your actual filter and when I starting to change the frequency the new values would be sent out and would create an infinite loop (and you also had the problem of saving off your original filter settings). Instead of changing the filtergraph itself, use an envelope to modify the frequency AFTER the filtergraph. I am attaching a simple monosynth patch I created which uses and ADSR for the amplitude and an ADSR for the frequency for the filter. The is a dial that allows you to change how much the frequency is affected by the filter envelope. I hope this help, it would be the first time I was posting on this forum without asking a question :)

Ed

— Pasted Max Patch, click to expand. —
Dec 28 2008 | 10:48 pm

Wired in pretty much the same way, doesn’t seem to work. Now you’ll understand why it’s so difficult for me to post my problem on here cause i have inlets and outlets going to different patchers, this is inside a poly.. do i need the output of my filter ADSR to go into [thispoly~] ??

If anybody would care to help me further I can send them my entire patch through email.

— Pasted Max Patch, click to expand. —
Dec 29 2008 | 7:20 pm

bump

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