Check out this crazy thing.
http://userwww.sfsu.edu/~hl/s.html
http://userwww.sfsu.edu/~hl/s.html
The 1954 Cook Binaural LP Disc and Binaural Phonograph Adapter
This adapter, shown mounted on a monaural Livingston phonograph arm,
allowed two monaural cartridges to play the twin record tracks.
Precise placement of the two needles at the beginning of the tracks
was always a problem.