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» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » Definition of "Mono Compatible"? (Page 1)

 
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Author Topic: Definition of "Mono Compatible"?
Michael Coate
Phenomenal Film Handler

Posts: 1904
From: Los Angeles, California
Registered: Feb 2001

- posted 02-17-2008 02:15 AM      Profile for Michael Coate   Email Michael Coate   Send New Private Message       Edit/Delete Post 
Is there some confusion over the definition of "mono compatible" in regard to those films mixed and released in Dolby Stereo?

When Dolby came on the scene, its mono compatibility was hyped as a major selling point and often recognized as one of the key reasons behind the company's/format's success. Nonetheless, during the late 1970s and into the 1980s, many (most?) titles mixed in Dolby Stereo had for any given market a double inventory of prints struck, with some in stereo and the balance in mono. (Never mind the 70mm and magnetic stuff; I'm referring to 35mm-optical.)

But what exactly was meant by "mono compatible"? Did it mean that prints with an optical SVA (Stereo Variable Area) track could be played in theaters equipped for SVA playback AND in theaters not equipped with the appropriate SVA decoding equipment? Or, did it mean that the MONO prints (of titles simultaneously released with STEREO prints) contained Dolby noise reduction but could still be played on conventional, non-Dolby sound systems?

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Darryl Spicer
Film God

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From: Lexington, KY, USA
Registered: Dec 2000

- posted 02-17-2008 03:03 AM      Profile for Darryl Spicer     Send New Private Message       Edit/Delete Post 
I would probably lean towards the fact that you could play the stereo soundtrack in a mono house with out problems other than the fact that the fader would have to be raised about 3db to compensate for the lower sound caused by the variable levels of the stereo track.

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Gordon McLeod
Film God

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From: Toronto Ontario Canada
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- posted 02-17-2008 09:41 AM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
One of the reasons (other than poor tracking in the early 110/116(or cat82 in a cp100) card( remember it only had a +/-2db gain riding on the centre to l/r channels ) for Dolby's requirement that dialogue be only in the centre channel was to maintain good mono compatiblty
The Academy curve masked the A type emphasis enough that the prints didn't sound too shrill though there was a note to turn the hiFreq down and the level was of course slightly lower

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Louis Bornwasser
Film God

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From: prospect ky usa
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- posted 02-17-2008 10:25 AM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
Daryll has it exactly. In the original Star Wars, I only remember one scene where the "mix" was not exactly the same: inside the Death Star, the "bottomless pit" has no echo when played stereo print in a mono house. Dialog was still good. Louis

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Bill Gabel
Film God

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From: Technicolor / Postworks NY, USA
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- posted 02-17-2008 10:39 AM      Profile for Bill Gabel   Email Bill Gabel   Send New Private Message       Edit/Delete Post 
As Darryl and Gordon said A Dolby Stereo print was compatible with anyone of the many mono sound systems around the world with just a minor fader adjustment. During those early years there was still many mono houses.

GCC had afew of the older plexes like Sherman Oaks, Santa Anita running mono into the 90's . Before the Northridge earthquake Sherman Oaks had 3 of 5 screens in Dolby Stereo and Santa Anita had 1 screen in Dolby Stereo out of 4. When GCC Beverly Connection converted 3 of their screen small houses to Dolby CP-65s the old front/surround units got installed at Santa Anita.
So Mono Compatible just met, if the theatre was still mono because the owner did not convert to Dolby Stereo he could still play the print.

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Thomas Pitt
Master Film Handler

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From: Leeds, West Yorkshire, UK
Registered: May 2007

- posted 02-17-2008 11:27 AM      Profile for Thomas Pitt   Email Thomas Pitt   Send New Private Message       Edit/Delete Post 
In my opinion, 'mono compatible' means the soundtrack can be played on a mono system with no noticeable impact on the mixing. It should sound like the entire 5.1 channels (or 2 stereo channels) have been mixed together into one single mono channel, and not have any adverse effects from this.

As recently as the first Pokemon movie, there were still mono problems. They made MewTwo's voice sound like it was inside your head by antiphasing one of the stereo channels. The downside of this was that if it was played on a mono system, the two waves would cancel each other out making MewTwo's voice virtually non-existant! This problem also occured when you played the VHS version on a mono recorder.

I have several stereo VHS tapes that have a 'mono compatible' sign on them, indicating they can be played on a mono recorder without any impact on the sound (as I mentioned above).

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Gordon McLeod
Film God

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From: Toronto Ontario Canada
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- posted 02-17-2008 01:08 PM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
Thomas said"In my opinion, 'mono compatible' means the soundtrack can be played on a mono system with no noticeable impact on the mixing. It should sound like the entire 5.1 channels (or 2 stereo channels) have been mixed together into one single mono channel, and not have any adverse effects from this."
No matter what you do the surround channel will be lost as it is recorded with a phase shift in the encoderof +90 and -90 degrees

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Scott Norwood
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From: Boston, MA. USA (1774.21 miles northeast of Dallas)
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- posted 02-17-2008 03:01 PM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
VHS is actually an interesting format, since it can carry three tracks' worth of sound. The linear track (which is roughly equivalent to cassette sound quality) can carry a mono mix and the hi-fi L/R tracks can carry the Lt/Rt (minus NR) tracks from the Dolby mix. A mono-only player will play the linear track and a stereo machine will play the hi-fi tracks by default but allows the mono track to be manually selected as well.

I don't know if anyone actually bothers to do this, or if it even matters when most mono listeners are using the 3" TV speaker.

I suppose that if anyone really cared, there would be a special "TV speaker" mix for the linear track, designed to sound good on crappy playback equipment.

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Stephen Furley
Film God

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From: Coulsdon, Croydon, England
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- posted 02-17-2008 03:06 PM      Profile for Stephen Furley   Email Stephen Furley   Send New Private Message       Edit/Delete Post 
There were a few VHS machines which split the linear track for two channel stereo; we had a couple of them at the school where I used to work. As might be expected the sound wasn't great. I think they had Dolby B on the linear tracks.

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Michael Coate
Phenomenal Film Handler

Posts: 1904
From: Los Angeles, California
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- posted 02-18-2008 01:57 AM      Profile for Michael Coate   Email Michael Coate   Send New Private Message       Edit/Delete Post 
If SVA prints were truly mono compatible, then why didn't the studios skip the double-inventory thing on their stereo titles and strike the entire batch of prints with the stereo track?

(You'd think that single-inventory would've been cheaper, would have cut down on some of the post-production time, and would have prevented the mis-delivery of a mono print to a stereo house.)

And regarding the mono prints (of titles mixed in and simultaneously issued in stereo): Were these DOLBY MONO or ACADEMY MONO?

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Monte L Fullmer
Film God

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From: Nampa, Idaho, USA
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- posted 02-18-2008 03:14 AM      Profile for Monte L Fullmer   Email Monte L Fullmer   Send New Private Message       Edit/Delete Post 
Going back to that empirical warhorse, "Star Wars", esp. with the original 1977 release, I remember, in the end credits, the Dolby Logo giving credit to "Dolby Systems - making film sound better" since our print was definitely a mono print at the time. (later on re-release prints were in Dolby "A" Stereo in the late 70's - including the 3dB reduction on the tracks were we mono houses had to boot the sound up a few notches)

From what I could tell is that the mono track was Dolby encoded to rid the hi freq noise that was present in the older Western Electic/RCA Sound recordings which the Dolby encoded print sounded better with our old Simplex tube amplifier and Altec A-7 speaker setup.

-Monte

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Christos Mitsakis
Expert Film Handler

Posts: 242
From: Ag.Paraskevi, ATHENS, GREECE
Registered: Sep 1999

- posted 02-18-2008 04:21 AM      Profile for Christos Mitsakis   Email Christos Mitsakis   Send New Private Message       Edit/Delete Post 
quote:
No matter what you do the surround channel will be lost as it is recorded with a phase shift in the encoder of +90 and -90 degrees
That's why early practice suggested to place a small amount of the surround information to front channels, to make the mix "mono compatible". Don't forget the "mono" compatibility check button on Dolby's professional decoders.

C.

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Greg Anderson
Jedi Master Film Handler

Posts: 766
From: Ogden Valley, Utah
Registered: Nov 1999

- posted 02-18-2008 02:37 PM      Profile for Greg Anderson   Author's Homepage   Email Greg Anderson   Send New Private Message       Edit/Delete Post 
quote: Michael Coate
And regarding the mono prints (of titles mixed in and simultaneously issued in stereo): Were these DOLBY MONO or ACADEMY MONO?
I ran a Mono print of Ghostbusters in 1984. We started the summer with Indiana Jones and the Temple of Doom in 70mm and, since we only had one stereo auditorium, we received a mono print of Ghostbusters. When Indiana Jones fell away earlier than expected, we moved Ghostbusters to our #1 auditorium in mono and we never got a stereo print (although we did receive a stereo 35mm print of Indiana Jones to move to a smaller house... and we never played that print in stereo. Go figure).

Anyway, I tried playing our Ghostbusters print in mono with Dolby noise reduction (format 02, if I remember correctly) and it just gave a less-than-desirable noise gate effect, essentially cutting out all ambient sounds in quiet scenes. So I quickly decided that was the wrong format.

quote: Michael Coate
(You'd think that single-inventory would've been cheaper, would have cut down on some of the post-production time, and would have prevented the mis-delivery of a mono print to a stereo house.)
Just speculation on my part, but did the studios owe licensing fees to Dolby and would a mixed inventory save a few dollars for the studios?

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Michael Coate
Phenomenal Film Handler

Posts: 1904
From: Los Angeles, California
Registered: Feb 2001

- posted 02-18-2008 05:47 PM      Profile for Michael Coate   Email Michael Coate   Send New Private Message       Edit/Delete Post 
quote: Monte L Fullmer
From what I could tell is that the mono track was Dolby encoded to rid the hi freq noise that was present in the older Western Electic/RCA Sound recordings which the Dolby encoded print sounded better with our old Simplex tube amplifier and Altec A-7 speaker setup.
quote: Greg Anderson
I tried playing our Ghostbusters print in mono with Dolby noise reduction (format 02, if I remember correctly) and it just gave a less-than-desirable noise gate effect, essentially cutting out all ambient sounds in quiet scenes. So I quickly decided that was the wrong format.
The above responses contradict one another. One suggests Dolby Noise Reduction was present on mono prints; the other suggests NR was not present.

I suppose the NR thing could've been handled on a title by title, studio by studio, year by year basis. I bring this up, though, because the "Was noise reduction present on the mono prints?" question is what motivated me to start up the thread. (The subject came up recently with another film-tech member in an off-site discussion.)

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Ron Curran
Jedi Master Film Handler

Posts: 504
From: Springwood NSW Australia
Registered: Feb 2006

- posted 02-18-2008 06:09 PM      Profile for Ron Curran   Author's Homepage   Email Ron Curran   Send New Private Message       Edit/Delete Post 
I believe that Greg is correct about a licence fee. My source stated a figure of $90 per print - not sure whether that was US or AU.

That is why we regularly received mono prints to play on our stereo equipment while the major mono cinema nearby received stereo prints. I am certain that the mono versions were Academy.

At the time, we were fortunate enough to be able to get the occasional mag print - I was mistaken in believing that the superior mag system would continue. The only reason we installed SVA was because the few SVA prints we ran on our mono system sounded crap.

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