A - I can think of several ways to account for your experience. If there was a minute particle of dirt on the play head, it would cause exactly the problems you heard during playback. By the time you rerecorded the three songs, the dirt particle had become dislodged, and everything was fine. If that was the case, your original should have been restored to fidelity also. A bad or misplaced pressure pad in the cassette shell could also cause your problems. but I canÕt imagine how it could repair itself. A third possibility is that somehow the cassette in question came too close to a strong magnetic field and suffered partial erasure. How or why? Well, twenty-five or so years ago when I was hired as technical editor of Popular Electronics , one of my first assignments was to construct an experimental flying saucer detector. The design was simple enough; it consisted of a finely balanced magnetic rod that when moved by external forces would trigger an alarm. It seems that flying saucers are notorious for the powerful, but erratic, magnetic fields they create. . . .