awesome, thanks a lot, really helpful. I was suspecting something like that, but couldn't get to this implementation.
And then, one question, doesn't the feedback given by tabsend theoretically count as a second delay line? cheers 2013/10/6 Mike Moser-Booth <[email protected]> > It's not that either implementation is wrong, they are just two ways of > doing the same thing. The version that uses two delay lines is the Direct > Form I. By doing some rearranging of the filter, you convert it to the > Direct Form II, which only uses one delay line. The end results are the > same, just one is more efficient. > > Look inside [pd allpass] in the attached patch for an ASCII art > illustration of it. > > > On Sat, Oct 5, 2013 at 3:35 PM, Alexandre Torres Porres > <[email protected]>wrote: > >> on curtis roads' computer music tutorial, page 418, it shows the same >> formula, but the figure of the design seems to contradict it. I'm confused. >> I don't seem to get the same result with one delay line. maybe if you send >> me a patch that sounds the same as cyclone's allpass I can check it. >> >> cheers >> >> >> 2013/10/5 Alexandre Torres Porres <[email protected]> >> >>> i dont think there is one way or proper way of doing this, and it is a >>> general form, from an equation you can find in other references. So, I >>> don't know why, but Max/Cyclone's allpass use this one: y(n) = -g x(n) + >>> x(n)-(DR/1000) + g y(n)-(DR/1000) >>> >>> >>> 2013/10/5 Chris Clepper <[email protected]> >>> >>>> That means cyclone's allpass~ is not done properly. Why not do it the >>>> standard and more efficient way? When it comes time to do dozens of >>>> allpasses it will make a difference. >>>> >>>> >>>> >>>> >>>> On Sat, Oct 5, 2013 at 1:00 PM, Alexandre Torres Porres < >>>> [email protected]> wrote: >>>> >>>>> but this way it won't be the same as cyclone's [allpass~], the way I >>>>> did it is equivalent to it (and max's). >>>>> >>>>> cheers >>>>> >>>>> >>>>> 2013/10/3 Chris Clepper <[email protected]> >>>>> >>>>>> You only need one delay line for the allpass. >>>>>> >>>>>> feedforward = input * -gain >>>>>> feedback = delayout * gain >>>>>> delayin = input + feedback >>>>>> output = delayout + feedforward >>>>>> >>>>>> http://www.spinsemi.com/knowledge_base/effects.html#Reverberation >>>>>> >>>>>> >>>>>> On Thu, Oct 3, 2013 at 11:29 AM, Alexandre Torres Porres < >>>>>> [email protected]> wrote: >>>>>> >>>>>>> i hope i guess i figured it out on how to implement it with delay >>>>>>> lines. see attachment. And I realize you can't do this with [fexpr~] or >>>>>>> [biquad~] because the sample delay length is kinda big for that, right? >>>>>>> >>>>>>> cheers >>>>>>> >>>>>>> >>>>>>> 2013/10/3 Alexandre Torres Porres <[email protected]> >>>>>>> >>>>>>>> cool, but do you know how to implement cyclone's [allpass~] with >>>>>>>> it? >>>>>>>> >>>>>>>> It's really unclear to me what is the relation of this pass filter >>>>>>>> with the one you can generate with biquad coefficients, or with raw >>>>>>>> poles/zeros objects for that matter. >>>>>>>> >>>>>>>> Well, one way or another, it's also unclear to me how to do it with >>>>>>>> delay lines. >>>>>>>> >>>>>>>> seems that it is related to a comb filter, right? >>>>>>>> >>>>>>>> cheers >>>>>>>> >>>>>>>> >>>>>>>> 2013/10/2 Chris Clepper <[email protected]> >>>>>>>> >>>>>>>>> Allpass for reverb is easy to do with delwrite~ and vd~. I used >>>>>>>>> 32 of them today to recreate a famous 'deep space' reverb. >>>>>>>>> >>>>>>>>> >>>>>>>>> On Wed, Oct 2, 2013 at 1:53 AM, Alexandre Torres Porres < >>>>>>>>> [email protected]> wrote: >>>>>>>>> >>>>>>>>>> hi there, i see the biquad's coefficients can be set as an >>>>>>>>>> allpass filter, generated by frequency and "Q" parameters. But can >>>>>>>>>> it do >>>>>>>>>> the same as cyclone's [allpass~] filer? If yes, them how since the >>>>>>>>>> parameters for [allpass~] are different (delaytime and such). >>>>>>>>>> >>>>>>>>>> One way or another, I guess that my real question is: how to >>>>>>>>>> implement [allpass~] from vanilla objects? >>>>>>>>>> >>>>>>>>>> thanks >>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> [email protected] mailing list >>>>>>>>>> UNSUBSCRIBE and account-management -> >>>>>>>>>> http://lists.puredata.info/listinfo/pd-list >>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>> >>>> >>> >> >> _______________________________________________ >> [email protected] mailing list >> UNSUBSCRIBE and account-management -> >> http://lists.puredata.info/listinfo/pd-list >> >> >
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