So...
Not that simple but my ideas are completely clear this time
Obviously, you need to have earphones that are sufficiently balanced and transparent (I don't like that word, but for lack of a better one...) in order to differentiate the filters.
- LA (Apodized Fast) : apparently, more "warm" (low medium), "musical" (human voices more present), punchy (bass)... The sound seems more loud ; but... slightly compressed dynamics, less air, less refined and systematism... Like a fainted coloration. My main complaint, and the compromised dynamics...
- LF filter (Fast Linear) : definitely the more
accurate in one word, everything considered, and... dynamics completely free. Best separation , best overall precision and definition, fastest transients... But... Sometimes, the truth can be... harsh.
Finally, with my Aure PrimeS plus Cadmus FE (let's say " warm neutral/balanced"), this is my very final choice : LF (Fast Linear).
I think it's the same with all the DAPs and DACs : Linear Fast = default accurate filter, with the less deformation of the original signal.
One important advice : take your time, over time (like one week LA filter, then one week the other), and avoid on-the-fly testing.
Otherwise, like me, you will heard some differences, but you'll be unable to choose, and then decide.