Wow! The audio quality must have been poor to say the least. Those old wire recorders were designed for frequency range of the human voice not music.
The only thing I remember with any certainty was the green eye!
I found it! https://en.wikipedia.org/wiki/Magic_eye_tube
This was so long ago that stereo, meant not one, but TWO SPEAKERS!
The wire recorder was momo, but unless you went to a fancy movie theater, sound was sound, some were louder, but mostly the same.
Yes, you could get a ‘reverb’ for your car!
And hit a bump it would make funny sounds.
A spring reverb!!!