The "Topping" table came from the manual for the E 30 II. The "AKM" table came from the evaluation manual for the AK4493S.
Here's the full page from AKM:
View attachment 539529
That default filter may indeed not be the best one to use, but then I have to wonder why AKM would make it the default and Topping leave it as the default. (Upon first setting up my E 30 II, the F3 filter was indeed what was in place as the default.)
I agree that what Amir shows as F2 and F6 look like what I would want to use. I just want to make sure that they're the same as what AKM/Topping call F2 (slow roll off filter) and F6 (low dispersion short delay filter).
To be honest, I would think that what I'd want would be a sharp roll-off filter. A slow roll-off one, to me, means that it has to start rolling off sooner, and thus would roll-off the highs in the audible range (pass band?) more than a sharp roll-off filter in order to reach a useful amount of attenuation at higher frequencies. Is that correct?
Hmmm.... I wonder if the rolled-off highs below 20KHz of the F3 filter are what constitute the "velvet sound?"