Jeff

Has anyone worked with adaptive filters in msp before? I'm trying to implement something similar to a feedback destroyer, and the idea I keep coming back to is using an adaptive filter to do the job. Is there an object I should look at?

http://ccrma.stanford.edu/~eberdahl/Projects/FeedbackCancellation/FeedbackCancellation.pdf,

 that makes reference to a Pd object that could potentially be ported over, but I'm hoping something already exists.

Has anyone worked with adaptive filters in msp before?  I'm trying to implement something similar to a feedback destroyer, and the idea I keep coming back to is using an adaptive filter to do the job.  Is there an object I should look at?

I found a reference online, here http://ccrma.stanford.edu/~eberdahl/Projects/FeedbackCancellation/FeedbackCancellation.pdf, that makes reference to a Pd object that could potentially be ported over, but I'm hoping something already exists.

adaptive-filters

I also found a tool by Peter Kassakian here:

http://www.cnmat.berkeley.edu/~kassak/Kassaksite_files/Software/MaxMSP/

I can't get it to run on my system, though. Mac OSX 10.4.10, Max/MSP 4.6.3 w/ Jitter 1.6.3, Intel Mac. I get the following message:

=95 error: linearprediction~: unable to load object bundle executable

2007-09-07 00:31:21.978 MaxMSP[490] CFLog (21): dyld returns 2 when

trying to load /Users/vautin/Documents/Audio/Max/AdaptiveFilters/linearpred=

I assume the external was compiled for PPC? I'm new to the externals game, so any information anyone can provide would be very welcome.

I can't get it to run on my system, though.  Mac OSX 10.4.10, Max/MSP 4.6.3 w/ Jitter 1.6.3, Intel Mac.  I get the following message:

 2007-09-07 00:31:21.978 MaxMSP[490] CFLog (21): dyld returns 2 when

I assume the external was compiled for PPC?  I'm new to the externals game, so any information anyone can provide would be very welcome.  

I'll try to round up the source for these and see if I can't make a working UB version.

Quote: Jeff wrote on Fri, 07 September 2007 06:25

----------------------------------------------------

> I also found a tool by Peter Kassakian here:

> I can't get it to run on my system, though. Mac OSX 10.4.10, Max/MSP 4.6.3 w/ Jitter 1.6.3, Intel Mac. I get the following message:

> =95 error: linearprediction~: unable to load object bundle executable

> 2007-09-07 00:31:21.978 MaxMSP[490] CFLog (21): dyld returns 2 when

> trying to load /Users/vautin/Documents/Audio/Max/AdaptiveFilters/linearpred=

> I assume the external was compiled for PPC? I'm new to the externals game, so any information anyone can provide would be very welcome. 

Quote: Jeff wrote on Fri, 07 September 2007 06:25
----------------------------------------------------
> I also found a tool by Peter Kassakian here:
>
> http://www.cnmat.berkeley.edu/~kassak/Kassaksite_files/Software/MaxMSP/
>
> I can't get it to run on my system, though.  Mac OSX 10.4.10, Max/MSP 4.6.3 w/ Jitter 1.6.3, Intel Mac.  I get the following message:
>
> =95 error: linearprediction~: unable to load object bundle executable
>
>  2007-09-07 00:31:21.978 MaxMSP[490] CFLog (21): dyld returns 2 when
>
> trying to load /Users/vautin/Documents/Audio/Max/AdaptiveFilters/linearpred=
>
> I assume the external was compiled for PPC?  I'm new to the externals game, so any information anyone can provide would be very welcome.  
>
> Thanks!
----------------------------------------------------


bump? gen. for the lower latency in feedback loops.

The http link above didn't work, but the paper is here:

https://ccrma.stanford.edu/~eberdahl/Projects/FeedbackCancellation/FeedbackCancellation.pdf

Source file for adaptfilt~ appers to be here: 

https://ccrma.stanford.edu/~eberdahl/Projects/AdaptFilt/proj/adaptfilt.cpp

Looks like it could be gen-ified. Making a start, will post if I make any progress.

The http link above didn't work, but the paper is here:
https://ccrma.stanford.edu/~eberdahl/Projects/FeedbackCancellation/FeedbackCancellation.pdf 

Source file for adaptfilt~ appers to be here: 
https://ccrma.stanford.edu/~eberdahl/Projects/AdaptFilt/proj/adaptfilt.cpp 

OK I believe I've ported the C++ source of adaptfilt~ to gen~ below.

AFAICT this object's purpose is, given a raw and filtered input, to extract a FIR model for this filter; and it does this very well.

If someone wants to pick this up to implement feedback suppression let me know & please post back here!

OK I believe I've  ported the C++ source of adaptfilt~ to gen~ below. 

AFAICT this object's purpose is, given a raw and filtered input, to extract a FIR model for this filter; and it does this very well.  

that is very helpful! I have only implemented adaptive filters offline in Python so far.

Next step would be to modify your patch and make a kernel adaptive filter - if I figure out how to do the memory management on the kernels, since this method is memory based (saves all old values, if no forgetting factor is introduced).

Maybe it's smarter to implement a training and testing function so I don't have to rely to heavily on that. Just thinking out loud here :)

that is very helpful! I have only implemented adaptive filters offline in Python so far.
Next step would be to modify your patch and make a kernel adaptive filter - if I figure out how to do the memory management on the kernels, since this method is memory based (saves all old values, if no forgetting factor is introduced).

Maybe it's smarter to implement a training and testing function so I don't have to rely to heavily on that. Just thinking out loud here :)

Adaptive Filters