Hi i'm new to the program and i'm trying to make an autofilter. The first problem i've come to is that lop~ doesn't have an input for a resonance control. How can i add resonance to my filter patch?.

welcome to pd land

well...theres a number of options, assumming that you're running pd-extended:

1- [vcf~] is a band pass filter with resonance

2- [svf~] is a multimode state variable filter (my favorite). It outputs low, high, band pass, notch simultaneously

3- [moog~] is a emulation of the moog ladder filter.

4- [reso-filt~] is both a 18dB/oct 303 type filter or another moog style.

5- iem-lib has loads of filters but can be fiddly and confusing

6- Cyclone has loads of MAX equivalents like [lores~] [reson~] etc

does this help you?

S

Thanks thats really helpful. I'm now trying to figure out how to control the filters attack and decay with an lfo, i'd ideally like to be able to switch between some waveforms and control lfo speed. I'm sure this is quite basic stuff but i'm totally new to this. Please could you let me know what objects i need to use or recommend a tutorial?.

some time ago i made this patch. it is a sort of lfo but only with sine, saw, and random wave types (i need only these...).
probably it is little naive, but works fine.

the left inlet is for frequency in Hertz (every frequency is accepted, so this not properly an LowFrequencyOscillator)
the righ inlet is for the wave type: 1 for sine wave, 2 for sawtooth wave, 3 for a random band-limited noise (similar to a random wave type, for this one you need cyclone library which is already in PDextended).

so you will have:

[audio~] [> ] [> ]
| | |
|______ [llfo~]
| |
[*~]

for sure there's a way to this with tabwrite~ and tabread~. maybe you can multiply [*~] your audio signal with an array you can draw/design yourself

http://www.pdpatchrepo.info/hurleur/llfo~.pd

I really appreciate the help but i'm a novice so i'm easily confused. At the momment i have a moog filter with filter freq and res. I followed a tutorial on the obiwannabe site for a basic synth which uses a line object for modulating the filter. I need to be able to trigger the filters with an lfo, i would like to have controls to choose between 3 waveforms and lfo speed. My PD knowledge really is minimal so what is a good starting point for this task?.

the patch i uploaded is a sort of lfo. just put it in the same directory of your project, so you can just create llfo~ object, or you can copy the dataflow of my patch, into a your subpatch.
you have to connect two number boxes to the object llfo~. the one connected on the left is the oscillating frequency (expressed in hertz), the other indicates the wave type of the oscillation (0=sine, 1=sawtooth, 2=random, 3= off)
then you have to multiply its outlet (with [*~] ) with your previous audio result (moog, freq and res)..

i hope i understood your problem and my answer is clearer, did i?

When you say an Autofilter you mean where the input controls or a sidechain
controls the cutoff frequency of the filter. So with a drum loop, you would have a rhythmic filtering effect.

have I miss understood you or have you already got it sorted ?

Cian- that made it a bit clearer, i'm still not sure on how to use it in my patch.

Boonier - My idea for an autofilter was to have an lfo control the filter cut off attack and release. And the audio input trigger the lfo. Do you know the best way of doing this?.

Hi folks

I know this is an old discussion but I didn't knew svf~ and moog~ and was so depressed for a long time because I couldn't change a cutoff frequency with some audio control on a lowpass filter.

THANKS A LOT boonier for this REALLY useful list of available filters in your first reply
You saved my day

Cheers,
Jo