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 Kyma Forum
 Tips & Techniques
 detect zero crossings
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| Author | Topic: detect zero crossings | |
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flo Member |
posted 03 December 2005 07:53
 
you'll find attached a simple sound which detects IP: Logged | |
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pete Member |
posted 05 December 2005 13:41
Hi Flo The problem with converting zero crossing to a global sound is that global sounds (and hot paramitors) are at control rate, so that if the signal is near 1 Khz you'll start to miss some crossings, and those that it does find will only be acurate to the nearest 1 khz border. To keep the zero crossing timing you will need to do every thing at sample rate and use sounds plugged in sounds to do it. This is one of the reasons I made petes DSP modules as they all work at sample rate. If you put your signal into a Gate to trigger module, you will get a pulse out every time the signal changes from minus to plus. If you wanted to reduce the number of pulses you can put this signal into a toggle module anf then put that into another gate to trigger module, it will miss out every other pulse. If you put that signal into another toggle module and GtoT you will only get every fourth pulse. To get every third is a bit tricky but it is pos. Hope this helps Pete IP: Logged | |
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flo Member |
posted 07 December 2005 06:19
thanks very much for the explanation. One thing after the other, first some things regarding the gate/ trigger/toggle-issue: Where can I find those GtoT modules, somewhere in the library? Is my conclusion right that with a GtoT module you already leave out certain zero-crossings, those where the signal goes from plus to minus? If so, you're not dealing with the most minimal, elementary wavesets. (not that this would be a drama, I just like to know this precisely) And regarding the toggling, you'll find attached an earlier attempt (had the idea already) to make a toggle out of a trigger with the 'asToggle' command, but I don't have the impression that it works properly, at least in this sound example. But you probably have a better way to implement this? Thanks in advance. Best, Florian IP: Logged | |
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pete Member |
posted 07 December 2005 09:06
Hi flo The modules are on the tweeky under Microsounds. http://www.symbolicsound.com/cgi-bin/bin/view/Share/Microsounds Yes your right with a single GtoT (Gate to Trigger) you will get one pulse per cycle (and that pulse will be only one sample wide), not one per half cycle (asuming the signal only crosses zero once in it's cycle). If you wanted a pulse for both the positive going and the negative going edge you would put two GtoTs in to an OR Gate module ( another one of the pete's DSP modules) or just a mixer and feed the signal directly into one of the GtoTs and indirectly to the other GtoT via a mixer with a gain of (- 1.0). This way the pulses will make a signal of twice the input frequency or some other sound if the input signal was not balanced in time. If on the other hand you wanted non thin pulses i.e. hi when the signal is positive and lo when the signal is negative then just use an "AsLogic" module but I think the thin pulse will be more usefull. Hope it helps Pete IP: Logged | |
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KX Member |
posted 07 December 2005 09:33
Speaking of logic modules, I think your microsounds (as well as Dave's)should be included with documentation in the next release of Kyma. IP: Logged | |
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pete Member |
posted 07 December 2005 10:31
I think I would need to tidy mine up quite a lot before they are added into the relyable and fully tested kyma code. IP: Logged | |
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flo Member |
posted 11 December 2005 16:12
Could somebody briefly instruct me how to integrate the .asy document to forgo the usound class error from kyma? (I suppose that's the problem why I can't play the microsounds right now) Thanks in advance. Best, Flo IP: Logged | |
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pete Member |
posted 13 December 2005 04:48
Hi flo First you must import the .asy file from within kyma. Then you must place it along side the Kyma app if you want it to auto load when kyma boots up. Otherwise you can select "Choose Microsounds" under the file menu in kyma if you want to load it up on a one off basis. Hope it works Pete IP: Logged | |
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flo Member |
posted 16 December 2005 04:00
Thanks, Pete, it works perfectly well now. IP: Logged |
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