ok tried to upsample the whole thing (after the osc~) and now change~ does nothing anymore… it just spits out the same square wave i feed in…clues?
On 27 Apr 2014, at 13:05, Simon Iten <itensi...@gmail.com> wrote: > crosspost! sorry about the noise. thanks for the inputs i will try to to > this. not sure if i can. otherwise i will ask back if that’s ok! > On 27 Apr 2014, at 13:03, Simon Iten <itensi...@gmail.com> wrote: > >> so if i would measure at the peak of the sawtooth and would upsample inside >> the pd patch, i would get higher resolution, right? >> >> any ideas how i can measure at the peak? (using the rpole output on both >> samphold inputs does not work and delaying one of them is also not working) >> >> which >> >> i would highly recommend you try this method with your gk-3 equipped guitar >> (one for each string) since you only have to cover a two octave range per >> string the error is tolerable. (you can add an offset to make it fit) >> On 27 Apr 2014, at 12:56, Miller Puckette <m...@ucsd.edu> wrote: >> >>> That is an excellent, witty way to measure pulse withs using >>> only tilde obects - my hat's off to you. >>> >>> The methond only has limited accuracy since its measurement is in >>> samples. For instance, a 1/2 cycle of a 440-hz. tone at 44.1 kHz is >>> only 50 samples, so there's only 2% accuracy. That's about 1/3 of a >>> half tone (30-ish cents) which would sound horribly out of tune. >>> >>> There's an alternative sine-to-sawtooth recipe described here: >>> >>> http://msp.ucsd.edu/Publications/icmc10.pdf >>> >>> This is the basis of my guitar processing patch, smeck, but should be more >>> broadly useful. But it has its own limitations: the sawtooth you get out >>> is wiggly if the input sn't a pure sinusoid. >>> >>> There's also the possibility of simply pitch tracking with sigmund~. Use >>> a maximum frequency around 6000 and a maximum of 6 partals (default 50!) >>> for best results. >>> >>> cheers >>> M >>> >>> On Sun, Apr 27, 2014 at 11:27:33AM +0200, Simon Iten wrote: >>>> dear list, >>>> >>>> i have a strange problem with my “sinetosawtooth” patch. >>>> >>>> it is basically a version of the pitch to voltage conversion used in the >>>> old gr300 guitar synths from roland. >>>> >>>> i cut out all the clutter to make it easier to look at and understand. >>>> (cut out the adaptive filtering at the input since i use a sine wave for >>>> this example and not a guitar string) >>>> >>>> here is how it works (or should): >>>> >>>> -an input signal gets amplified by a large factor and clipped. this >>>> squares the input. >>>> >>>> -the square wave is converted to pulses. >>>> >>>> -the pulses from the rising of the square wave are used to set and reset >>>> an accumulating filter (rpole~) >>>> >>>> this results in a sawtooth wave that varies in amplitude depending on the >>>> frequency of the input. >>>> >>>> -a sample and hold samples the peak of the sawtooth and holds it until the >>>> next peak occurs. this, after a conversion gives us the input frequency. >>>> yeah! >>>> >>>> in the example patch i used the falling edges of the square wave to >>>> trigger the sample and hold. this samples the sawtooth amplitude after >>>> half the rising. (this is also why i have 22050 in fexpr~ and not 44100) >>>> i could not figure out how to sample the peak of the sawtooth, so >>>> suggestions here are very welcome. >>>> >>>> now to the problem: >>>> >>>> the extracted frequency does not exactly correspond to the input >>>> frequency. it is pretty close at low frequencies but gets worse at higher >>>> frequencies. the factor is not constant. at even higher frequencies >>>> (around 5000 hertz) the reported frequency gets totally out of control. >>>> >>>> i first thought this is because the samphold~ object is inaccurate. but i >>>> then saw that the sawtooth wave from the rpole~ object has no constant >>>> amplitude even with the input frequency not changing. so it seems that >>>> either rpole~ or change~ is not accurate. >>>> >>>> or the problem is that i sample in the middle of the rising and not at the >>>> top ( as described earlier) >>>> >>>> attached the sinetosawtooth patch. set your sound card to 44100 or change >>>> the 22050 in fexpr~ to half the sampling frequency. >>>> >>>> i would really appreciate if somebody could have a look at this, >>>> >>>> thanks, simon >>>> >>> >>> >>>> _______________________________________________ >>>> Pd-list@iem.at mailing list >>>> UNSUBSCRIBE and account-management -> >>>> http://lists.puredata.info/listinfo/pd-list >>> >> > _______________________________________________ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
