Editing 8-track cartridge (section)

=== Discrete Quadraphonic 8-track ===
Four-channel 8-tracks were distinguishable by the notch in the upper left hand corner as in the picture to the right. Blanks such as this one were sold with a white spacer occupying the notch the same as [[45 rpm adapter]] were sold to convert 7-inch (19&nbsp;cm) large hole singles so that they could be played on conventional turntables. This notch activated the second set of tracks on the new head which would have originally played Programs 3 and 4 of a stereo tape and used them simultaneously with heads that would read Programs 1 and 2.

Tapes were first marketed for the Fall, 1970 music season. Oddly, the last [[Stereo-Pak]] four ''track'' Muntz cartridge tapes (vs four ''channel'' quadraphonic) were still being produced at the same time as well as regular Stereo 8 tapes.