From the original SynthMaker forum (2004–2014), with its members’ names and dates.
Rellik ·
I'm trying to create a comb filter - not actually too sure how to do it [from what I've been able to read it looks just like a first-order IIR filter with delays on the y(t) delayed inputs that are greater than one (and perhaps variable). Is this right? Sorry, I just started learning about digital filters last week, and I really want to figure out how to make that interesting comb sound 😀]
Anyway, I know that it involves this delay of multiple samples. SM has a component that takes a MONO signal and delays it by X number of samples - how would I make it take a POLY signal? or is there some better method of doing this?
Also, in the code component: can you use arrays? Because I could figure out how to make it have long delays if I could use an array to store the samples and delay them... it's less appealing than the Poly Multiple-Sample Delay module, though.
Shifrin ·
I've been after (along with a few others) a Poly Delay for a little while now (I'm sure we'll have it sooner or later). It's not implementable in the code component for now as we've no arrays. So, you'll have to stick with the Mono Delay! If you want to take your 'poly' signal into a 'mono' Delay then you just convert it with a 'Poly2Mono' component!
As for comb filters, there's some great information here :-
You'll find a comb filter in the Freeverb port I did to SM too - although it has a damping 'lowpass filter' in it's feedback path.
Shif.
Rellik ·
Thanks, Shifrin! In fact, I had already been looking at your schematic - it's ok that it's mono because it's an effect, right? Poly can be converted to mono, but it's too bad it can't go the other way around -
By the way, thanks for the link, but I don't think it works 🙁 I'll see if I can mess with the URL to make it work
Tom7777 ·
The url works fine for me, that site is one of the best for info on filters/dsp ect and i have been using it for a while now, basically it has everything you might need if you can work out how to convert it. 🙂
Shifrin ·
Rellik wrote: Thanks, Shifrin! In fact, I had already been looking at your schematic - it's ok that it's mono because it's an effect, right? Poly can be converted to mono, but it's too bad it can't go the other way around -
Yeah it fine for it to be mono, I wanted a poly one for some physical modelling stuff. You can AFAIK convert mono back to poly using a, umm, I forget the name - some sort of 'pack' module. It takes four mono inputs and converts them to a poly output!
Rellik wrote: By the way, thanks for the link, but I don't think it works 🙁 I'll see if I can mess with the URL to make it work
Hmmm, weird, works fine for me. Like Tom said, one of the best DSP/Filter sites on the net 🙂
Shif.
stefan ·
Shifrin wrote:
Rellik wrote: Thanks, Shifrin! In fact, I had already been looking at your schematic - it's ok that it's mono because it's an effect, right? Poly can be converted to mono, but it's too bad it can't go the other way around -
Yeah it fine for it to be mono, I wanted a poly one for some physical modelling stuff. You can AFAIK convert mono back to poly using a, umm, I forget the name - some sort of 'pack' module. It takes four mono inputs and converts them to a poly output!
That's not really what it does. It takes four mono's and packs them into SSE component, so if you tried to play more than four poly channels it wouldn't work 🙂
I use it in Nildon, in the mono section, to use a filter on four mono channels.
ik ·
😮
Is it not a tunable delay with z-1 feedback?
Don't we need to wait for non-static delay (or array in the code comp ...)
to make a feedback comb f. and/for any related phys. mod. experiments?
ik.
Shifrin ·
stefancrs wrote: That's not really what it does. It takes four mono's and packs them into SSE component, so if you tried to play more than four poly channels it wouldn't work 🙂
Yep, I understand it now, jorge posted something on it 🙂 Learn something new everyday here, great place!
Cheers Stefan,
Shif.
Shifrin ·
ik wrote: :o
Is it not a tunable delay with z-1 feedback?
Don't we need to wait for non-static delay (or array in the code comp ...)
to make a feedback comb f. and/for any related phys. mod. experiments?
ik.
Not sure exactly if I understand you, you can implement a comb with feedback, but not a one with fractional delay time which can be modulated at sample rate. And it's only 'mono' for now, so it can't be used for polyphonic PM stuff. Umm, then again I could be wrong! 😉
Shif.
ik ·
you can implement a comb with feedback, but not a one with fractional delay time which can be modulated at sample rate. And it's only 'mono' for now, so it can't be used for polyphonic PM stuff. Umm, then again I could be wrong!
No, you are right.
That is exactly what I ment. When we get the Delay with fract delay time, we'll have a tunable comb filter in 2 minutes.
ik.
chironex ·
Sorry to bring back the dead, but...
We most certainly have Fractional Delay now, and I've been trying to find a +/- Comb for my FX plug I'm working on. So, would anyone be able to whip one up?
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