http://en.wikipedia.org/wiki/Super_8_film#Sound has the following: "Super 8mm was also specified with an optical sound track. This occupied the same location as the magnetic track. Picture to sound separation in this format was just 16 frames. Projectors and cameras obviously could not record sound in this system, but optical sound package movies became briefly popular, particularly in Europe (mainly because they were cheaper to produce - though the projectors cost more). Although the optical sound should have been inferior in quality to magnetic sound (running at 3.6 inches per second for 24 frames per second), in practice it was often much better, largely because packaged movie magnetic sound was often poorly recorded." No mention of audio tracks in any form in the Regular-8 article however. Arno