[PD] [biquad~] as max's phaseshift? (was [biquad~] as cyclone's [allpass~]?)

[Alexandre Torres Porres]

Anyway, next on my list is finding out how to implement max's
[phaseshift~], which is also an allpass filter. There's no Pd clone for it
so it seems, right?

Well, it doesn't really what it is other than a 2nd order filter. From that
I could think you can generate it with [biquad~], but the phase response
given in phaseshift's help file suggest otherwise.

any contributions welcome

thanks a lot

2013/10/5 Alexandre Torres Porres <porres at gmail.com>

> 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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