8MM FORUM WORLDWIDE • View topic - Unusual optical soundtrack

8MM-16MM FORUM WORLDWIDE

The International Forum for 8mm, 16mm, and 9.5mm film
Dedicated To Collectors Around The World
It is currently Thu Mar 28, 2024 3:23 pm

All times are UTC - 5 hours [ DST ]

Click on any of the boxes below to link to a new page



Screening Rooms    Ebay Film Sellers    Film/Equipment Sellers    Laurel and Hardy    Magnetic Striping


Our mission is to provide a "free" forum for all members. This forum will not delete, lock up, or edit any posts. On this forum, you are "free" to question any statement that is not understood, and debate any differences you have with another member. We only moderate when a member will not back up his accusations. There are no condescending attitudes from the Administrator or the Moderator. You will be treated with respect. Dan Lail, Admin. and Chris Smith, Moderator



Post new topic Reply to topic  [ 22 posts ]  Go to page Previous  1, 2, 3  Next
Author Message
 Post subject: Re: Unusual optical soundtrack
PostPosted: Fri May 08, 2015 1:45 pm 
Offline
Film Expert
User avatar

Joined: Thu May 26, 2011 1:36 pm
Posts: 732
Ken Layton wrote:
That's a "push-pull" variable density track. The two tracks are 180 degrees out of phase with respect to each other. I have one of those tracks on a 16mm trailer for The Day The Earth Stood Still.

That track on your 16mm print is probably a reduction from a 35mm print. To properly play it back you need a push-pull optical sound head (common with 35mm soundheads) which has a phototube with two pickup elements inside it like a type 920.



What was the purpose of the out of phase tracks, Ken?

Do 16mm projectors exist with such an arrangement?

_________________
www.mickoregan.com


Top
 Profile Send private message  
 
 Post subject: Re: Unusual optical soundtrack
PostPosted: Fri May 08, 2015 1:52 pm 
Offline
Film Expert
User avatar

Joined: Wed Apr 02, 2014 2:42 am
Posts: 70
Location: Olympia, Washington
Push-Pull tracks were intended to be used in a theater sound system which had a push-pull phototube in the soundhead and used an amplifier with a push-pull output stage. This was to give greater sound output with less noise, a primitive noise reduction system so to speak.

If a push pull track was played on a normal sound head, it would have a reduction in volume. This is much like playing a Dolby stereo optical track on a mono soundhead. Yes it plays back, but at lower volume.


Top
 Profile Send private message  
 
 Post subject: Re: Unusual optical soundtrack
PostPosted: Fri May 08, 2015 2:35 pm 
Offline
Film Expert
User avatar

Joined: Thu May 26, 2011 1:36 pm
Posts: 732
Interesting.

How about 16mm projectors with this system? Do they exist?

Well, Robert, there's your answer.
:smile:

_________________
www.mickoregan.com


Top
 Profile Send private message  
 
 Post subject: Re: Unusual optical soundtrack
PostPosted: Fri May 08, 2015 5:06 pm 
Offline
Film Expert
User avatar

Joined: Wed Apr 02, 2014 2:42 am
Posts: 70
Location: Olympia, Washington
I don't know for certain which 16mm machines would have been capable, but it would have definitely been one with a tube amplifier containing a push-pull output stage and a phototube for the optical sound pickup. Probably one that used either an 868 (mono) or 918 (mono) phototube which could be directly interchanged with a type 920 (push-pull or stereo).


Top
 Profile Send private message  
 
 Post subject: Re: Unusual optical soundtrack
PostPosted: Sat May 09, 2015 7:09 am 
Offline
Film Expert

Joined: Tue Apr 14, 2015 4:09 am
Posts: 147
Location: Oxfordshire
I received an email from Paul Ivester which had done the rounds with members here. There is a difference in the scan of my soundtrack and the one I received of a push pull soundtrack. On mine both tracks are identical. I am using a Bell & Howell 655 and the film plays normally.
Attachment:
optical.PNG
optical.PNG [ 204.12 KiB | Viewed 9017 times ]


Top
 Profile Send private message  
 
 Post subject: Re: Unusual optical soundtrack
PostPosted: Sat May 09, 2015 7:28 am 
Offline
Film Expert

Joined: Tue Apr 14, 2015 4:09 am
Posts: 147
Location: Oxfordshire
I have a quad variable area soundtrack in 16mm, is this unusual?


Top
 Profile Send private message  
 
 Post subject: Re: Unusual optical soundtrack
PostPosted: Sat May 09, 2015 11:46 am 
Offline
Film Expert
User avatar

Joined: Wed Apr 02, 2014 2:42 am
Posts: 70
Location: Olympia, Washington
Robert Crewdson wrote:
I have a quad variable area soundtrack in 16mm, is this unusual?


Sounds like you have a "Maurer" track which is actually 6 tracks. It's explained on page 606 of the book I referenced earlier.

Very common track.


Top
 Profile Send private message  
 
 Post subject: Re: Unusual optical soundtrack
PostPosted: Sat May 09, 2015 12:32 pm 
Offline
Film Expert
User avatar

Joined: Wed Apr 02, 2014 2:42 am
Posts: 70
Location: Olympia, Washington
Robert:

After examining your variable density track more closely, it's not push-pull. It's a dual variable density I have never seen before. Do the two tracks stay exactly alike throughout the entire print?


Top
 Profile Send private message  
 
 Post subject: Re: Unusual optical soundtrack
PostPosted: Sat May 09, 2015 2:05 pm 
Offline
Film Expert
User avatar

Joined: Thu May 26, 2011 1:36 pm
Posts: 732
Ah, it remains a mystery. This is the first interesting topic I've come across on any of the forums in a while.

_________________
www.mickoregan.com


Top
 Profile Send private message  
 
 Post subject: Re: Unusual optical soundtrack
PostPosted: Sun May 10, 2015 11:02 am 
Offline
Film Expert

Joined: Tue Apr 14, 2015 4:09 am
Posts: 147
Location: Oxfordshire
Here is are 2 images of what I called Quad Variable Area. You can see that it has 4 tracks, not the 6 of the Maurer.
Attachment:
quad.PNG
quad.PNG [ 263.47 KiB | Viewed 8995 times ]


Top
 Profile Send private message  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 22 posts ]  Go to page Previous  1, 2, 3  Next

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 6 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
cron
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group