Dobrescu George
Reviewer: AudiophileHeaven
These filters are a built-in dsp function of ESS Sabre DACs And if you are playing mp3s and using less resolving iems - you probably won't hear much of a difference.
I'm almost always using FLAC for everything and HD for what bands can be found in, and the most resolving IEMs I generally have. The differences still aren't night and day, even with the most detailed IEMs out there, like say ER4XR, the differences exist, but I wouldn't lose sleep over it.
Wow! Impressive analysis. I hope iBasso presents similar description (guidance) as a part of the manual, like other manufacturers.
ESS has a guide (they make the DACs), and there are tons of tests around that show similar results, but again, the differences are supposed to be pretty small, the rule of thumb is that the more pre and post echo you'll have, the more likely you're to like that sound. Kinda like how folks like the filter setting on iDSD BL to be set to Standard, which will sound like this, and some folks like it on Bit-Perfect which has the minimum filtering usually a Brick Wall.
Sorry, but I can't find a quick reference, but you should be able to, if you look enough.