Odd really, Cassette as a medium, home recorded for portable use, is OK.
I've had a couple of good cassette players (best was a panasonic one with
dolby B and C, and with reasonable tapes there was plenty of treble.

In the late 80s when cassette walkmans were at their most esoteric and
expensive, I owned the top of the tree (apart from the Sony WM-D6C, which
could hardly be called a "Walkman" in the sense of being small and
portable), and believe me, they all lacked proper treble.

I have minidisc now for use in pocket trains, and a portable CD in my bag
for music in hotel rooms.

I use a Minidisc too now, and it has treble.

YMMV of course.


Martin