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

[Alexandre Torres Porres]

> the phase response given in phaseshift's help file suggest otherwise.

it's more like the response from miller's H14 example...

So I guess you can have a 2nd order one (lie phaseshift) by putting two of
these together, right? And I suspect it doesn't really need to have
anything to do biquad just for being "2nd order", huh?

cheers


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

> 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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