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 crossFilter | what it does in detail
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| Author | Topic: crossFilter | what it does in detail |
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johannes Member |
posted 01 September 2013 11:03
 
hello all, at the moment pete´s crossfilter is one of the greatest sound design features that iam about to explore in kyma. i wonder if there is a documentation about the kyma crossfilter implementation on the kyma tweaky site i once read that kyma crossfilter implementation is a fir based technic, but iam not sure about that (generally its fft based, right?)... cant find the link anymore. thanks, johannes
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gustl Member |
posted 08 October 2013 14:42
also interested in this! IP: Logged |
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phillipm Member |
posted 09 October 2013 07:34
Also interested. I also wonder what it would take to create a leaner (i.e. "lite") version of the process that still has longish capture times. Obviously that would have to be at the expense of something else... IP: Logged |
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gustl Member |
posted 09 October 2013 09:38
as far as I know the crossfilter long is exactly that! but for more complex Sounds a lite version could be useful... still I don't know how it works exactly.. I tried the following today: 2 Samples (source and response) both fed into the fft module then I multiplied the ffts and had an ifft module to convert it back again. In parallel the same samples are being crossfiltered. I wanted to compare between these two but i didn't get any sound out of the fft one... (if anyone was successful doing convolution this way please let me know) anyway I think the crossfilter is not a basic convolution process. but what do I know?  pete programmed it, maybe he can give us some more information? IP: Logged |
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SSC Administrator |
posted 09 October 2013 13:42
The CrossFilter is non-trivial. It would not be easy (and likely not possible) to re-create it using other Kyma modules. But since you have it in your hands, why not just use it to create new sounds and effects? IP: Logged |
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pete Member |
posted 09 October 2013 16:23
Hi I think SSC is right. If there was any way to make it out of standard Kyma modules I would not have spent 2 years writing the DSP code. I think it is as lite as SSC and I can make it. I think running kyma at lower sample rates would give you proportionately longer responses for the same processing power, but I doubt that is the expense you would want to pay. Hope this makes sense Pete IP: Logged |
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gustl Member |
posted 10 October 2013 00:49
I didn't mean to rebuild it with kyma modules and I didn't think it's possible... We just want to know what it does  no need to share the whole dsp code (wouldn't understand it anyway) but just a little bit more detail about the processing. and, yes, I use it a lot to make new Sounds because it is a fantastc prototype IP: Logged |
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RobSol Member |
posted 10 October 2013 14:16
The cross-filter uses a process called Convolution to do its magic, which is essentially the same technique used in reverbs that have impulse responses of a real space loaded into them. IP: Logged |
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gustl Member |
posted 11 October 2013 05:10
I don't think so because the technique used in common convolution reverb plugins wouldn't have taken pete 2 years of programming IP: Logged |
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johannes Member |
posted 11 October 2013 12:52
thanks for all the replies, robsol, do you think that the calculation of the signals happens in the frequency domain by a complex multiplication? i searched the max documentation and found this (see the last third of the paper called "convolution and cross synthesis"): http://www.cycling74.com/docs/max5/tutorials/msp-tut/mspchapter26.html and gustl, even if your patch doesnt work i would like to see it... just to get an idea. IP: Logged |
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RobSol Member |
posted 11 October 2013 18:38
Well, I am only guessing of course... Cross-synthesis and convolution are usually two different words for the same thing. IP: Logged |
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SeanFlannery Member |
posted 12 October 2013 17:06
There is a sound (or timeline) I came across a while ago called Rendezvous With Rama that is a big bad cross filtering example - Capy users with less than 8 processors may have difficulty running it. I dont recall where I dug it up, I've had a poke around the Tweaky and a search through this forum today and cant find it but I highly recommend checking it out and deconstructing it. It's a moody atmosphere sound - one of my all time Kyma favourites. Be advised it has a very very long fade in It may not leave you with any better idea of what cross filtering in Kyma does but it will bend your mind when you compare the inputs to the cross filter to what is being output. I cant get to my Kyma system right now so I cant search the sound library. Perhaps someone else here can advise where to find this remarkable example. regards, IP: Logged |
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SeanFlannery Member |
posted 14 October 2013 19:30
Found it! at http://www.symbolicsound.com/cgi-bin/bin/view/Share/Sounds#Synthesis_ under Crossfading, morphing, and other transitions you will find MovingWindowConvolutionsexamples.kym This is the direct link to the file: http://www.symbolicsound.com/zzz/pub/Share/CrossfadingMorphing/MovingWindowConvolutionsexamples.kym IP: Logged |
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gustl Member |
posted 14 October 2013 23:20
@johannes sorry I don't have a patch to share I just made some experiments and it's quite a mess. but basically I just tried to build someting like in the max tutorial.. thanks for sharing this wonderful Sound, Sean. And thanks for creating it, Cristian IP: Logged |
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johannes Member |
posted 18 October 2013 00:14
for everybody who likes to understand convolution in more practical way, i recommend this very clear and nice written description of convolution (with a lot of audio examples) at the soundonsound website: http://www.soundonsound.com/sos/sep10/articles/convolution.htm#Top IP: Logged |
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SeanFlannery Member |
posted 18 October 2013 00:58
Ooooo!!! Hi res audio examples and impulse responses accompany this article which can be dwonloaded as a set from http://www.soundonsound.com/sos/sep10/articles/convolutionaudio.htm Awesome Thanks for posting this johannes!! IP: Logged |
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gustl Member |
posted 22 October 2013 01:23
Also for a more technical background check: http://www.dspguide.com/pdfbook.htm Excellent book and free IP: Logged |
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gustl Member |
posted 28 November 2013 04:39
Check out the "Cross Input w/Forced air heater" sound in Effects processing / Cross Synthesis / spectral cross synthesis.kym Worth it! IP: Logged |
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