For recording, a tape head functions as a small electromagnet powered by the audio signal. The current flowing through its coils induces a magnetic field that penetrates the tape and alters the magnetic state of the tape particles. During playback, this process is reversed: The magnetic field of the tape is picked up, inducing an electrical current in the head’s coils. A 2-head cassette deck uses a single head for the recording and playback functions. The second head is for erasing. This design produces fine results in both recording and playback. If you do a lot of recording, stepping up to a 3-head deck has several advantages. It uses separate heads for play, record, and erase for better performance. With each head optimized for its singular task, you’ll enjoy better recording and playback performance — including improved frequency response — than you would with a 2-head deck. Also, 3-head decks are arranged so that the erase head comes first, the record head second, and the playback