Hi Timothy,

Well, it's probably my fault that we've gotten so far off the "16MM mag sound film" subject, but I've found it informative as far as updating my dated experiences with film.  In latter years, I was lucky to move over to digital editing which became the better tool for me to do what I had first learned to do with a Moviola and film bench.
Ironically, your mention of the mag-striped 20th Century Fox Cinemascope release prints brought back how I started on my film career in 1955 as a theater projectionist in my off-duty hours in the Army.  I'd been only doing it a few months when they installed the first Cinemascope system at the main theater.  I had the thrill of running "The Student Prince" in stereo and surround sound with Mario Lanza singing those ringing high C's.  I couldn't believe I was making a few extra dollars to hear and see this new marvel.  Little did I realize that I had also been bitten by the movie bug which launched me into my final Hollywood career. I'm sure others of our group can tell of such life changing events.  God moves in mysterious ways, etc.....
--- On Thu, 8/19/10, timothy wilson <[log in to unmask]> wrote:
From: timothy wilson <[log in to unmask]>
Subject: Re: [ARSCLIST] help: 16MM mag sound film
To: [log in to unmask]
Date: Thursday, August 19, 2010, 7:20 PM

I would say that 3-trk is A standard, and not THE standard.  Originally 3-trk 
was for mono recordings with separate dialog-music-effects (DME) as well as for 
stereo music elements in a left-center-right (LCR) configuration.  In 1953 Fox 
began making fullcoat 4-track LCRS(urround) mixes to accompany their new 
Cinemascope format.  This included putting 4 thin mag tracks (2 on each side of 
the perfs) on the release prints to be played in the theaters.  6-track mixes 
have been around since at least the late 70s, and when I worked in film editing 
this was the format that was delivered on fullcoat 35mm mag for the final print 
master, as well as for all the test screenings we did.  Usually the basic 
configuration for this was(is) LLcCRcRS (also referred to as a 5.1 sound), with 
the S being the subwoofer, or boom.  Sometimes the 2nd and 4th channels are baby 
booms.  70mm release prints have 6 thin mag strips surrounding the perfs.  Also, 
there are Dolby stereo matrix prints, which are L and R tracks recorded on a 
3-track head, with the 3rd track blank.  The 2 stereo tracks essentially become 
LCRS when played through the Dolby matrix.  This configuration is called LtRt 
(Left total-Right total).  

I'm just scratching the surface here, and the non-engineer in me is probably 
screwing up a lot of the technical descriptions, but just wanted to give my 2 
cents of experience.

Tim Wilson
Audio Mechanics