REQ and Sigma Studio (Analog Devices)

ssashton

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Hi All,

I'm trying to get my head around SigmaStudio from Analog Devices which is the means to interface with their DSP audio chips such as the ADAU1452 (board I got), or the ADAU1701 used in MiniDSP 2x4.

I just wondered if there is a way to get REQ to output filter coefficients in a format suitable for SigmaStudio?

Also am I right assuming all filter coefficients are IIR filters regardless of the 'hardware' selected in the EQ menus?

Thank you,
Simon
 

ssashton

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P.S. why can't I post links to other sites such as for SigmaStudio and the Analog Devices chips?
 

John Mulcahy

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Might be too soon after registering or too few posts for links. The filters are all biquads, if you use the Generic setting the filter biquad coefficients can be exported to file in a format miniDSP use. Note that a1 and a2 are negated.
 

ssashton

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Hello,

Thanks for your reply. I've tried using the Generic and also MiniDSP2x4 options to export filter coefficients to use in SigmaStudio.

Firstly I found all of the formatting must be removed to have only the coefficient, one per line without commas, or labels.

However even then, once I have the data imported it does not behave as expected.

I think I've read that SigmaStudio works with 8.24 format. What does REW export? I must admit I find these various formats confusing.

Is there a way to get this working?

27798
27799
 

ssashton

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Oh, that's it! Thanks!

When you said they are negated I had thought you simply meant to pay attention to the sign.
 

ssashton

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How could I request a setting be added to export the file in a compatible way without needing to manually remove all non-decimal formatting and reverse the signs?

Boards based around the SigmaStudio architecture are only going to become more popular with cheaply boards from AliExpress and totally open designs from places like FreeDSP.cc

I'm sure there are other people like myself who struggle with maths but want to build stuff around the platform.
 

ssashton

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How many filter entries does SigmaStudio allow in a file?
To my knowledge, the user needs to cascade second-order filters and load the coefficients for each. So one bi-quad per text file.

Perhaps there is a way to load the data for all in one hit, I'll ask on the Analog Devices forum.

Thanks for considering this!

EDIT: Scrap that I found how! You can have 16 bi-quads per file :)

Formatted as a pure list of the coeffiencets one per line, only minus signs and decimal allowed. E.g 2 bi-quads:
0.9982198958597709
-1.9950375681982182
0.9968448836247746
-1.9950375681982182
0.9950647794845456
1.0113887958521648
-1.9728808287481057
0.9657251856964669
-1.9728808287481057
0.9771139815486316
 
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John Mulcahy

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I have added an option for the SigmaStudio format for the Generic equaliser, but it will export as many filters as are selected on the filter panel so it would be a bit tedious to make individual coefficient files.
 

ssashton

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I have added an option for the SigmaStudio format for the Generic equaliser, but it will export as many filters as are selected on the filter panel so it would be a bit tedious to make individual coefficient files.
Amazing, thank you John!
 

SteffenV

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EDIT: Scrap that I found how! You can have 16 bi-quads per file
I'll just repeat your own answer from the analog forum (this is an URL so type https:// in front (the forum didnt allow me as im to new to it): ez.analog.com/dsp/sigmadsp/f/q-a/120489/load-multiple-iir-coefficients-from-one-txt-file/358016#358016), so that others also can read here the mini trick of "right click: Open:Load IIR Coefficients from file" on the 2nd Ord Gen Filter.
 
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