[PD] [biquad~] as cyclone's [allpass~]?

Alexandre Torres Porres porres at gmail.com
Sat Oct 5 19:30:51 CEST 2013

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 <cgclepper at gmail.com>

> 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 <porres at gmail.com>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 <cgclepper at gmail.com>
>>
>>> 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 <
>>> porres at gmail.com> 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 <porres at gmail.com>
>>>>
>>>>> 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 <cgclepper at gmail.com>
>>>>>
>>>>>> 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 <
>>>>>> porres at gmail.com> 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
>>>>>>>
>>>>>>> _______________________________________________
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>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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