# [PD] from poles/zeros to biquad coefficients - how to? (something like max's z-plane)

Alexandre Torres Porres porres at gmail.com
Tue Sep 24 14:51:46 CEST 2013

```hey joe, this blog is awesome, I stumbled upon it too, they even have an
applet that does the job I want, but no code or formulas around :P it's the
closest thing I found on the subject in the internet...

weird how I can't seem to find these formulas on google and all...

cheers

2013/9/24 Joe White <white.joe4 at gmail.com>

> Hey Alexandre,
>
> This blog - EarLevel Engineering<http://www.earlevel.com/main/2003/02/28/biquads/> -
> really helped with my understanding of poles/zeros and biquads. Hope it's
> useful!
>
> Cheers,
> Joe
>
>
> On 24 September 2013 06:36, Alexandre Torres Porres <porres at gmail.com>wrote:
>
>> for what i see, it's not some sort of straight formula, right? seems a
>> bit more complicated than that.
>>
>> cheers
>>
>>
>> 2013/9/23 Funs Seelen <funsseelen at gmail.com>
>>
>>> On Mon, Sep 23, 2013 at 5:35 PM, Alexandre Torres Porres <
>>> porres at gmail.com> wrote:
>>>
>>>>
>>>> thanks, here's a pic of what I have so far
>>>>
>>>>
>>>> https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/11212_10151872996046683_1825736206_n.jpg
>>>>
>>>
>>> Cool.
>>>
>>>
>>>>
>>>> > For extra inspiration you could have a look at PoZeTools
>>>>
>>>> It sure does look like what I need. Thanks. But extracting what I need
>>>> to know about the math of converting from coordinates to coefficients was
>>>> just over my head :P unfortunately, sorry.
>>>>
>>>> I was hoping for something simpler, like just the operations needed. If
>>>> the info is in code, I need it to more explicit. I'd really appreciate if
>>>> anyone knows how to read from this and just points it out for me so I can
>>>> put it in a patch.
>>>>
>>>> I'm assuming it's rather simple math
>>>>
>>>
>>> I remember I once learned how to do this but never repeated the
>>> practice. If I find time to do that I would gladly try to figure it out
>>> again, but if someone more experienced feels the urge to chime in before
>>> that time I would be very happy too :).
>>>
>>
>>
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>
>
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