Hi Folks,

I decided to make a thread about this topic, because I did not find any answer about my question on the net.
Recently I found this doc about a very old audio interface (Digital Audio Denmark ADDA 2402):
https://www.digitalaudio.dk/media/4aid.pdf
In this document they are introduce the new feature of the interface - the "NF stop-band filtering for eliminating the risk of AID"
The complete guide is about that topic and how to eliminate the issue.
They mentioned that the majority of converters have 0.45/0.55 anti-alias filters, except the CS5397 from Crystal Semiconductors which was installed in ADDA 2402.
I did a quick research and I found that the chips in some today popular device such Focusrite scarlets has a "stopband" of the internal anti alias filter at 0.58 Fs.
e.g. Cirrus Logic CS4272 or the new CS5381:
https://statics.cirrus.com/pubs/proD.../CS5381_F3.pdf
So it seems that the chip and interface manufacturers not involved to solve this issue. Why not?
Is this "AID" realy an issue? If it is, why not every chip anti alias filter has a stopband at 0.5 Fs?
Or if it is not a problem (anymore), why not? Maybe that feature was just a good marketing for the device?

Thanks in advance, if anyone has a good answer on this.