WHat did Audiophiles hear during Tape deck era?

First a couple of snarky answers: (1) they listened to music, (2) nothing, because none of us used the term "audiophile" in those days.  Enjoyed a Sony RTR machine for years, later a Nakamichi 1000 that my brother and I bought jointly (used, because they were so darned expensive!).  Added a dox noise reduction unit later on; pretty darned good results for the era. That equipment is long gone, although I still have a couple hundred cassettes in the closet.

I WILL take those cassettes off your hands. Name your price.

I wouldn't have called myself an audiophile back in the 70's;  I was just doing what everyone else in my group was doing - my teen/early 20's years.  Making my own mix cassette tapes with selected songs pulled from my records, trying to get the sound level just right without distorting, keeping the break between songs to a couple of seconds.  I had both an 8-track and cassette deck for my car that I could swap out for each other with a bracket under the dash.  I had a few acquaintances that did RTR, but that never would have been a good solution for me, as I listened to most of my music in my car (lived in an apartment, small bedroom, very thin walls).  I bought a Technics SL-1200 just so I could speed up the last song on a tape ever so slightly so that it would fit.  TDK ruled the day; first getting the cheapest (and longest running) 10-pack I could, then buying the better ones as time went on if I could get deals on them.  Maxell came next, then Denon.  I still have my discrete head Nakamichi DR-10 (never could spend what, $1800 for the Dragon?) and it doesn't get a lot of use nowadays - need to change the belts and rubber wheels - but I was surprised how good some of my tapes sounded with my current system.  The 8-tracks never sounded good and were a nightmare to repair if they got eaten by your machine, so they didn't last long with me once I got into cassettes.

I still have a Harmon Kardon HK 2000 cassette deck. I used it to make tapes for the car. It was a good deck back in the day. Don't know why but can't bring myself to get rid of it. Nostalgia I guess.

I still have my Denon 3-head deck from 1991 in my system as well as my old mix tapes. It great to play back these old tapes and remember the good times from that time. It is good nostalgia.