Chinon Sound Issue

[Brad Kimball]

Replaced belt. Air dusted all components. Took a fine thin paint brush and ran it gently along the side of the audio assembly. Sound is "bubbly". You can definitely make out what's being said, but there's a sort of vibrato especially when there's music. Picture is steady and clear, but the audio sounds a tad gargly.

[Joseph Banfield]

Sounds like what is known as "film chatter" to me. This chatter only occurs on Super 8 sound films. It usually occurs during loud audio portions on the soundtrack. It happens on some machines because the distance between the picture and audio is only 18 frames. With such a short distance the audio track goes through the sound head still fluctuating from the pulldown of the claw. I believe on some of the Elmo machines there is a small pinch roller before the sound head that entirely eliminates this problem. On standard 8mm film the picture and sound are seperated by 54 frames and this chatter can never happen because of the much longer seperation between picture and sound. There is no cure for chatter and some machines produce it while others don't. And many people think their machines do not have this problem only to find they actually do when adding an extension speaker or running the sound through an external amp or listening using headphones.

[Steve Klare]

I had this once where it became much better after I installed a new set of guides. My best guess is wear on the chute flattening the film after the lower loop was allowing the stripe to bounce on the head even more than usual.

I run through external speakers all the time, and every so often I hear a hint of it through the speakers. I guess it's always there, lurking below the surface. Fortunately our ears and brains are good at picking out the strongest signal and ignoring the noise. This is why hum isn't a problem until the sound gets quiet.

Is the problem on all films? If it's on some, I wonder if lubing them will help. If it's on all of them maybe the chute over the head isn't closing fully.

[Chip Gelmini]

I have often heard the term "WOW & FLUTTER."

Wouldn't this be the FLUTTER issue. Sounding more like a rattle or machine gun from a gangster movie.

Whereas the "WOW would be unstable or "wobbly" sound - the way a boat rocks on a wave, etc. Tone and pitch varies.

[Steve Klare]

Yes, much more "flutter" than "wow". (To me, wow is much harder to ignore: it's almost painful!)

This sound is similar to the sound the claw makes, basically because the movement of the claw causes it. That's the reason people hear it more through external speakers or headphones: the claw mechanism's sound masks it when the machine is on internal speaker (-kind of like trying to pick out one trumpet from twenty).

[Chip Gelmini]

Steve you should consider a GS1200 they do NOT have this problem

I have had other Elmo projectors which had the wow and flutter problem so I am very familiar with what we are discussing in this thread ever since I switched to the GS 1200 I have not had flutter EVER.

I have WOW once in awhile but that means my speed for take up via Tower setup needs to be adjusted as the GS is only producing light and sound and is not doing the spooling......

Chip

[Joseph Banfield]

Knowing absolutely nothing about Chinon projectors and how they thread, which I assume would be totally automatic, there is a little trick that can be done. On a Eumig 701 or 709 the threading is not fully automatic and the machine must be manually threaded after it exits the gate. On these types of machines you can increase your bottom loop by a frame or two thereby creating a larger picture to audio distance like 19 or 20 frames...this would also eliminate the film chatter. But it may not be possible on a fully automatic threading machine because the film could be scratched if it touches anything in the loading mechanism by creating a larger lower loop.

There is also the possibility that the film chatter was recorded onto the film during the recording process from another machine. In that case you would never fix the issue unless the soundtrack were rerecorded. I would test it with another sound film from a different source to be sure.

[Maurice Leakey]

Brad has not told us what model Chinon he is referring to.


Maurice

[Brad Kimball]

7000MV and 6100. Both have the sound "bubbly" effect. Not my Eumig S802 with the same reel of film. The sound on the Chinons is clear and loud. It just sounds a tad like it would if one were slightly under water, but clear. Like bubbles. Both Chinons have it. Especially noticeable during music and singing.

[Joseph Banfield]

Yep, that's what you got for sure, the well-known film chatter problem. Since your Eumig does not show this symptom you can be sure there is nothing wrong with your film. Like I said above, some projectors have this problem and others do not, even among the same models. The Bauer (Silma) T 171 and the Eumig S 701 do not have this issue even when isolating the sound from the projector (external speaker, mixing console or headphones). On the other hand my Bolex SM 80 (Eumig 800 series in disguise) chatters on every single loud passage, which is why I only use it for silent films. Film chatter was known and reported back in the 1960's and remains a problem today...

[Maurice Leakey]

Brad
I have many Chinon sound projectors, including a 6100, but have never had any problems with the sound on them.
Pay attention to the two rollers after the sound head, the small one has a flywheel attached. Make sure it moves quite freely.
Also check the rubber roller, is it quite clean and does it revolve without any drag?


Maurice

[Brad Kimball]

Thank you, fellas! This forum is the best!