How does 8-track work?
by Abigail Lavine
The 8-track cartridge contains a length of 1/4 inch tape which runs in a continuous loop at 3 and 3/4 inches per second (ips). The tape is wound around a hub in the middle of the cartridge. It pulls out from the center and follows a path which brings it across the front edge of the cartridge where it makes contact with the playback head. A pressure pad helps to bring the tape into proper contact with the head. The pinch roller, which is inside the cartridge, presses against the capstan, which is part of the player. The tape, pinched between the roller and the capstan (which is spun by the player's motor), is thus moved across the head. The tape itself is divided along its length into 8 channels or tracks (hence the name "8-track").
The tape head plays two tracks at a time--stereo! A metal sensing strip connects the ends of the strip of tape, forming the loop. Here's where the real 8-track magic happens. When the tape reaches the end of a program, the metal sensing strip connects with a solenoid coil in the player. This coil causes the playback head to shift along the width of the tape. This is the loud "click' or "clunk" sound you hear between 8-track programs. The playback head, shifted to it's new position, begins to play the next program in the sequence. This process can go on indefinitely, running through each of the four programs in sequence, until the world ends, or your batteries wear out, or the tape breaks.
Other information on this topic:
Troubleshooting 8-track Tape Problems
Troubleshooting 8-track Player Problems