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Topic: optical stereo from a Holmes?

Bruce McGee
Phenomenal Film Handler

Posts: 1776
From: Asheville, NC USA... Nowhere in Particular.
Registered: Aug 1999

posted 07-20-1999 06:35 AM

Naturally! it figures. I would buy the machine that is like no other.

On looking at a Dolby optical track on an old print that I just bought, I notice that there is a slight difference in the left and right track placement on the film. I mean, one starts about 1/8" before the other. When I was doing the coarse alignment of the sound optics, it was impossible to use this film and get any decent sound quality. There was no "happy medium." Is a Dolby trait? I dont have the bucks to shell out for the decoder unit that I obviously need.

I am looking around the house here to see what I might have that I can use for a mounting surface for a pair of solar cells placed inside the PE cell cover the way the current set-up is done. I removed the cell that Brad gave me from the holder. I held it in place with a pair of needlenose and it tests a bit better on my meter than the cell I am using at this time. Hopefully, I can use it.
I appreciate all the ideas that I am getting here.

Unfortunately, I have to make a living for a few weeks, and I cant do much on this subject, but I will do what I can...

Bruce McGee
Asheville, NC

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Ken Layton
Phenomenal Film Handler

Posts: 1452
From: Olympia, Wash. USA
Registered: Sep 1999

posted 07-20-1999 01:20 PM

Bruce:
The stereo (SVA) optical track is recorded 45 degrees out of phase.

It should be possible to get an old Eprad Starscope (or Starlet) or Smart or Ultrastereo for next to nothing from some of the cinema supply dealers to use with your Holmes.

If you feel really ambitious, how about coming up with a Dolby Digital basement reader setup for the Holmes!

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 07-20-1999 05:02 PM

The SVA track is not recorded 45 degrees out of phase.
L is encoded into lt in phase
r is encoded into rt in phase
c is encoded into Lt and RT at .707 each in phase
The squirly part is the surrounds
They are recorded 180 degrees out of phase ie
Lt contains in phase surround
Rt contains the surrounds 180 degrees out of phase
On decoding the decoder uses + and - 90 degree phase shifts to extract the constant components and then feeds them to a side chain to generate the gain riding coefficients
The 45 degree phase shifts are only used for the surround ex encoder

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Bruce McGee
Phenomenal Film Handler

Posts: 1776
From: Asheville, NC USA... Nowhere in Particular.
Registered: Aug 1999

posted 07-21-1999 01:30 PM

Since the only theater supply house near here is 100 miles away, and I have to work here, I hope to find something here from you fine people that I might use. The Holmes is ill-equipped for many modifications. This one has the take-up reel on the front of the machine below the lens.
If anybody wants to see what one looks like, before the paint-job, just E-mail me personally, and I will send a picture taken a few months ago.

Bruce McGee
Asheville, NC

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