When was the first eight track player inventted when was the first cassette tape player inventted?

Lear moved on to yet another challenge: the perfection of an endless magnetic loop recording and playback system. As early as 1946, Lear had been interested in audio recordings; after experimenting more seriously in the early 1960s, he created the eight-track tape player. Lear's tape contained four stereo "programs," running in parallel on eight "tracks," for the entire length of a single, continuous tape loop. A solenoid coil detected the splice where the loop was closed, and sent a signal to the playback head to shift over to the next pair of tracks at that point. Because Lear's system had thinner tape and compact recording heads, this shifting process could be repeated indefinitely. Lear's system was a great improvement on the esoteric four-track players that already existed; it was also a huge marketing success. From 1965 well into the 1970s, Lear's eight-track players made their way from Lear jets and Ford cars into the homes of virtually every music enthusiast.