Hi, Christie,
While they are used interchangeably in many instances, the tracks are 
what are actually on the tape and the channel often refers to the 
electronics chain.
The area where this is most confusing is in consumer formats where the 
bulk of consumer tape machines were quarter track (or four-track) 
STEREO, meaning they only had two channels of electronics.
Another consumer area is the 8-track cartridge. While there were 8 
tracks on the tapes, most players could only play two at a time, while 
some could play four at a time.
But other than this subtlety, I wouldn't worry about it. I think I 
generally use "tracks" more than channels when talking about tape, 
however, as the head lays down tracks on the actual tape.
I think I've referred you to the pictures at
http://richardhess.com/notes/formats/magnetic-media/magnetic-tapes/analog-audio/025-reel-tape/ 
same graphic, but the other half of the info:
http://richardhess.com/notes/formats/magnetic-media/magnetic-tapes/analog-audio/025-cartridges/ 
http://richardhess.com/notes/formats/magnetic-media/magnetic-tapes/analog-audio/015-cassettes/ 
Cheers,
Richard
At 10:28 AM 10/16/2006, Christie Peterson wrote:
Question for today:  what, if anything, is the physical difference 
between a "channel" and a "track" when speaking about magnetic tape?
Are the terms just used to describe different ways in which the same 
physical phenomenon (separate bands of information on the magnetic 
tape) can be employed, or is there not even a difference on that level?
Thanks!
--
Christie Peterson
Project Archivist, Muskie Archives & Special Collections
Bates College
70 Campus Avenue
Lewiston, ME 04240-6018
(t) 207-753-6918
(f) 207-755-5911
Richard L. Hess                   email: richard@xxxxxxxxxxxxxxx
Aurora, Ontario, Canada       (905) 713 6733     1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.