Hi Klaus,
The filters are necessary to obtain a -1 +1 range, I think.
import("stdfaust.lib");
correlate(l,r) = l*l ,r*r , l*r : par(i,3, si.smooth(0.9)) : sqrt, sqrt, _ :
*,_ : /;
correlate_meter(x,y) = x,y <: x , attach(y, (correlate :
hbargraph("corr”,-1,1)));
process = correlate_meter;
Try playing with the si.smooth coefficient.
best,
giuseppe
> On 3 Aug 2021, at 14:09, Klaus Scheuermann <kla...@posteo.de> wrote:
>
> Could it be something like this?
>
> (according to the 'correct' algorithm in
> https://www.beis.de/Elektronik/Correlation/CorrelationCorrectAndWrong.html )
> import("stdfaust.lib");
>
> correlate(l,r) = l*l ,r*r , l*r : sqrt, sqrt, _ : *,_ : / :_;
> correlate_meter(x,y) = x,y <: x , attach(y, (correlate :
> hbargraph("corr",-1,1))) : _,_;
>
> process = _,_ : correlate_meter: _,_;
>
> I am not sure about the lowpass filters though. Maybe not needed in the
> digital domain?
>
> Also, my code only returns -1 or 1 while it should be returning a range of -1
> and 1, right?
>> The correlation is either expressed in % from -100% to +100% or as the
>> correlation factor, which ranges from -1 to +1. Note that due to the
>> correlation algorithm the level of both signals does not matter, i.e., it
>> does not influence the measured result.
>>
>> When a mono source is used for a stereo signal both stereo channels will be
>> +100% correlated. When e.g. in a stereo signal both channels contain
>> completely different signals, e.g. left (and only left) is the trumpet and
>> right (and only right) is the guitar these stereo channels will be 0%
>> correlated. With a third instrument appearing in both channels, the
>> correlation will be somewhere between 0 and +100%.
>>
>
> Ideas?
> Danke :)
> Klaus
>
>
>
>
> On 03.08.21 12:48, Klaus Scheuermann wrote:
>> Hello List,
>>
>> I just wondered, if anyone has implemented a stereo audio correlation
>> meter/analyser in faust?
>>
>> If yes - great!
>> If no - I have another project :)
>>
>> Here is what I found about the algorithm(s):
>>
>> https://www.beis.de/Elektronik/Correlation/CorrelationCorrectAndWrong.html
>>
>>
>> I never learned analog electronic schematics, but it seems it should not
>> be extremely hard to transfer to faust.
>>
>> Cheers, Klaus
>>
>>
>>
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