ADAU1467 Low-Shelf filter How to calculate filter coefficient

I believe that is a typo. S=2πf/Fs.

Hi Ken,

Thanks,

What you mean is S = 2 * pi * omega ., right ?

What do the "omega" mean ?

Not ω0 = 2*pi*f0/Fs but ω(omega).

Thanks and Regards,

Sorry. I've corrected my answer.

Hi Ken,

Thanks,

In conclusion, what is correct?

Regards,

I stumbled across this question and didn't want to leave it unanswered...

Capital "S" - in this case - is the abbreviation of a normalized tuning parameter called "shelf slope" that is related/analogous to the quality and/or bandwidth parameters of standard biquads. You could certainly put S in terms of either Q or BW, but it wouldn't have much real meaning.

Rather than write a bunch more, I'll only quote this:

When S = 1, the shelf slope is as steep as it can be and remain monotonically increasing or decreasing gain with frequency. The shelf slope, in dB/octave, remains proportional to S for all other values for a fixed f0/Fs and dBgain.

from here: http://shepazu.github.io/Audio-EQ-Cookbook/audio-eq-cookbook.html

Go there to find all of the good details.

Hi DJMaguire,

Thanks for detailed information.

I have one more question about "Crossover Filter".

There are crossover type options in following document page.

https://wiki.analog.com/resources/tools-software/sigmastudio/toolbox/filters/crossover

Please let me know, especially if you know the difference between each Linkwitz-Riley 12/24/36/48 .

Thanks and Regards,

Sorry for the delay. I am only just now seeing this. The choices for the Linkwitz-Riley crossovers of 12/24/36/48 should be simply the desired choice of dB/octave magnitude slope. It's simply an alternative to asking for order, I suppose.

Thank you.