Wheels Of Fire was prac. destroyed by this. Take a master tape, play it on to a takeup reel at 15 ips. Nice even packing. Store it that way until next time, tails out. Uneven rewind, take that same tape and rewind it at fast speed so it's heads out. The tape is not packed evenly. After being stored like that for 20 years or more, warped, uneven sound, etc. Engineer error. Common but not tragic, just stupid.