sorry this one went off-list :-)
On 27 Apr 2014, at 19:05, simon <itensi...@gmail.com> wrote: > sure, > > here is the version with biquad in a subpatch with a block opject to > upsample. probably i'm doing something wrong, i just copied from the block > help-patch. > > <sinetosawtoothupsample.pd> > > On Apr 27, 2014, at 5:48 PM, Miller Puckette wrote: > >> Drat, I don't have any explanation for this... can you send me the patch >> again? >> cheers >> M >> >> On Sun, Apr 27, 2014 at 05:44:22PM +0200, simon wrote: >>> hmm, changing change to biquad does also not work. i mean it does as long >>> as i don't upsample in the subpatch. as soon as i change the block object i >>> get square instead of pulses... >>> >>> On Apr 27, 2014, at 3:48 PM, Miller Puckette wrote: >>> >>>> Actually I don't know where the change~ object is from - I've nver seen t >>>> before. I would just use biquad~ 0 0 1 -1 0 (assuming that change~ simply >>>> ubtracts the previous sample from teh current one as I guessed from the >>>> patch :) >>>> >>>> M >>>> >>>> On Sun, Apr 27, 2014 at 03:40:01PM +0200, Simon Iten wrote: >>>>> 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
