Old 35mm Sound Alignment Films - Query

[Sam Chavez]

I believe the Midway version used DBX on the battle scenes. 45 minutes of ships shooting volleys. That sure scared the mice and rats living in this dump of a theatre. I'd see the rodents run by and they'd hide behind the film cans.

But I digress!

[Mark Ogden]

Apparently there were installation issues arising from the difficulty involved in reading the low frequency tones through some of the theatre sound systems which existed at the time.

The theatre where I ran Earthquake never got the trigger tones to work right, so we wound up manually hitting the test button on the generator to trigger the effect. I remember that there were red cue dots on the print at the appropriate scenes, one to hit the button and one to let up on it.

[Mark Gulbrandsen]

I can only remember going to the Oakbrook, IL Plitt Theater to see Midway and noticing that the outside of the building was shaking from the Sensurround. And it was a fairly large, massive stone building at that. I also have no Doubt that Kintek (DBX) was involved since there were lots and lots of problems. When I worked for Classic Cinemas, we even had many failures of their regulated exciter supplies.Turns out that every one they made failed.

[Sam Chavez]

To Marks point regarding Oakbrook, The level of the subwoofers was set by a measured voltage at the amp speaker terminals and not sound pressure level. The loudness varied wildly between venues. I had the usual Radio shack SPL meters due to my work with Dolby processors. I hit 135dB in an old building and there was sand like dust coming from overhead so backed off right quick while a more modern room was barely hitting 120. Also, we installed the speakers Universal shipped at suggested locations within the cinema which usually involved removing seats. We have come a ways since then.

[Mark Gulbrandsen]

Once the great downtown Chicago Palaces closed, mainly Cinestage and Michael Todd, The Oakbrook and Woodfield were the best theaters around. That was an interesting way to set SPL on Sensurround! SPL meters back then were big! I think the only portable SPL meter back then that had digital read out was made in Great Britian, however, the Rat shack meter actually worked pretty good for $29.

There was at least one theater somewhere in Chicago that eventually had plaster fall from the ceiling due to a Sensurround engagement.

When Star Wars came out I saw it once a week for something like 8 weeks on my way home from working at Canon. Then Plitt twinned the Oakbrook and ruined it. They didn't even bother to move the projectors, they just pointed them at the new screens center. The last movie I saw at Oakbrook was Silkwood.

[Robert Harrison]

That downtown Chicago theatre that temporarily suspended using Sensurround was the United Artists (not part of the UA chain, as the name might indicate, but actually a Plitt Theatre at that time; the building has since been razed). Apparently, this was only for a week, as these ads from January 1975 show. Notice the first ad has an empty space where the Sensurround logo should have been. Sensurround off an on again.jpg

[Mark Gulbrandsen]

That downtown Chicago theatre that temporarily suspended using Sensurround was the United Artists (not part of the UA chain, as the name might indicate, but actually a Plitt Theatre at that time; the building has since been razed). Apparently, this was only for a week, as these ads from January 1975 show. Notice the first ad has an empty space where the Sensurround logo should have been. Sensurround off an on again.jpg

Yea, too many of the down town theaters are gone in all cities. In Chicago, the Woods, United Artists, Michael Todd, Cinestage,Clark, Etc. They did manage to save the facades of the Michael Todd and CInestage, (Originally Harris & Selwyn Theaters) but the new Stage theaters behind those facades is all relatively new and only used for live shows. The Bismark (Previously Palace Cinerama) is still 100% intact inside and out but has been renamed The Palace Theater and is only live stuff now. The Oriental is all restored and intact too. but they changed the name to James M. Nederlander Theater. Chicago Theater is all restored and far as I know can still run film. A set of VIc 10's I had at one time ended up in that booth in a round about way. Last film I saw there was Steamboat Bill with Buster Keaton and Safety Last with Harold Lloyd, accompanied by Gaylord Carter on the Chicago's Wurlitzer. It is the oldest Wurllitzer in existence and the first musical instrument to be granted landmark status. It was used as a compliment to stage shows & silent films during the theatre’s first three decades of operation.

[Jim Cassedy]

<edited> What was the name of the color based optical sound system. ...

Back in the late 70's & early 80's, when it became apparent that multi-channel film sound was
not just a passing fad, there were a number of different systems proposed in an attempt to
compete with Dolby, which at that time pretty much was the 'only player in the game'. While
looking up something totally unrelated to this topic last week, I stumbled upon a series of
patent filings from between 1979-1981 for a "Fluorescent Sound Track Readout System",
in which the digital encoded audio bits would be printed over the picture area of the film
"using compounds which are colorless and transparent to visible light, but which flouresce
in the visible spectrum when exposed to ultraviolet light."
So, the idea was to "print" the digital sound 'bits' over the picture area of the film, using
some sort of invisible ink - which would not affect the image at all, but which would glow
when exposed to ultraviolet light in the sound reader. The 'glowing bits' would then be
picked up by a photodiode array, and the bitstream then got decoded into analog audio for
amplification. The inventor claims multi-channel capability over the full audio spectrum. I'm
not sure if such a system was ever built, or even if it was practical, but it's an interesting idea.

[Sam Chavez]

Dolby studied the fluorescent approach and a number of other ideas before settling on the the SR.D blocks between the sprocket holes. I for one did not believe it would work having worked in cinemas and observing what happens to film. Glad to say I was wrong.

[Gordon McLeod]

Sounds like sensouround as the two tones are the trigger tones on the first sensourond film. The 400 was i think to set the level for the DBX expander

[John Eickhof]

Mark, that test reel was great! The opening is identical to the MPRC sound quality test reel I have from Altec Service! Even the piano notes are the same ones! My test reel is approx 5 minutes to but is strictly mono. If memory serves correct the film scenes are the same too...just mono! Altec listed it as ASTR-3 variable density and ASTR-4 variable area track.

[Gordon McLeod]

Also 400 hz was the most often used tone with wow and flutter meters

[Mark Gulbrandsen]

Mark, that test reel was great! The opening is identical to the MPRC sound quality test reel I have from Altec Service! Even the piano notes are the same ones! My test reel is approx 5 minutes to but is strictly mono. If memory serves correct the film scenes are the same too...just mono! Altec listed it as ASTR-3 variable density and ASTR-4 variable area track.

John... If you listen to it in stereo it actually works. The voice follows the dot!!

[Mark Gulbrandsen]

Also 400 hz was the most often used tone with wow and flutter meters

My Leader W&F Bridge uses 3 kHz... Screenshot_20240216-185958-846.png

[John Eickhof]

Mark, I still have a Perspecta integrator from the Los Angeles theatre, I sold my other one to Dick Prather years ago, he restored it (re-capped and rebuilt freq traps) and I watched White Christmas in his screening room (with a density track!) it sounded great! I have a 20min VV promo reel, we played that and the sound worked great too! It was also IB Tech and had a density track!