The dupe machines used to run at something like 16X real time for pre-made cassettes and up to 160X real time for tape-only copy before assembly.
If you ran the tape-only copiers too fast the tape would burst into flames, which is probably the only thing that kept speeds from getting higher.
16X real time doesn't give the head a lot of time to kick the tape particles around, so the high end on most recordings started to roll off somewhere around 6-8k.
But most players couldn't play anything over 12k anyway, so not many people noticed.
The brain can reconstruct a lot of information - what it finds hard to process is complex spatial reverberation. A lot of recordings today mix all kinds of delays, echoes and reverb in the same track so that the brain cannot 'reassemble' the space. (A function I guess of software that makes it easy to insert a chain in any channel). It is quite tiring to listen to. A stereo recording with a Blumlein pair is a lot easier to listen to, even with limited frequency range and media noise. You can't be me, I'm taken
I noticed that I used to enjoy music more on cassette, presumably because my brain was filling in what it wanted to hear because there was so little real detail there.
That didn't change until I ripped all of my CDs to disk - which makes a bit-perfect copy of the CD master - and started playing them through decent converters.
Now I wonder how I ever put up with vinyl or tape.
I don't find the processed sound tiring - it's been processed for a while now, and I more or less grew up with it.
But it is hard to find really good engineering now, and many (but not all) recent albums seem to sound wretchedly bad - thin, grainy, heavy-handed - compared to some of classics from the 70s, which also had plenty of fake reverb and echo, but managed to hold it together more satisfyingly.
The engineer at my favourite studio in Stockholm in the Seventies modded the Dolby A's there - and Dolby bought his mods. He later became house engineer for Abba - and whatever you think of the music, it's great engineering. You can't be me, I'm taken
