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Tim Gillett

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    Why is this sound so bad with a Lasergraphics scanner?

    in Post Production

    Posted · Edited by Tim Gillett

    3 hours ago, Tyler Purcell said:

    Ahh yea, I did look at that, doesn't run on Apple silicon or our new PC Ryzen PC lol 

    So we can't even run it on any system we have according to their documentation. Have you tried it on Apple Silicon or AMD CPU's with Windows 11? If it works, I will for sure start using it because it appears to be a good tool. 

     

    I've only used the free trial version of Capstan on Win 10  which I used to process the above sample. Other products I know of are Cedar Respeed, and Izotope RX since version 8 I think. I guess you'd need to look up the manufacturer's notes for compatible OS's.

    There's also of course Plangent Process but it requires special equipment, skills and a steady audio or bias tone printed into the source material as a speed reference. 

    Why is this sound so bad with a Lasergraphics scanner?

    in Post Production

    Posted · Edited by Tim Gillett

    It's already been said by Frank Wylie that music especially some types of music is far more revealing than speech, of audio wow.

    That's why in the film Daniel linked to, the wow only "appears" at the beginning and closing minutes of the film.  But only because the music only appears at the beginning and the end of the film.  The wow still there right through the film but since most of the film is mere voice the wow not nearly as perceptible to  human listening.

    Anyone truly familiar with traditional sound movie projectors knows that sound movie film projector design presented a basic mechanical problem. The requirements for projection of the picture and for sound in terms of film  speed were almost completely opposite. The picture had to be stop/start/stop/start while for sound the film had to travel at a very smooth and unwavering speed.  

    To help with this, most projectors had a jockey wheel system whose function was to somewhat isolate the speed  flywheel system from the wild stop/start variations in film speed necessary at the film gate.  This system was not perfect. It was a tradeoff. It reduced flutter (fast speed variations) while unfortunately introducing new slow speed variations  (wow). What we hear in the sample soundtrack above is classic wow that we might hear in a traditional film projector, or even telecine chain. Depending on the state of maintenance of the projector or telecine, the wow could vary in its intensity.

    Re the LG  I understand from Perry the 80,000 samples per second frequency avoids the AEO's far more crude "sampling" of say a mere 24 samples (frames) per second so avoids inter frame timing issues within the optical track (recurrent clicks and pops), but it doesnt in itself control for film speed anomolies. Apparently the LG  has a system of very accurately measuring or controlling film speed at the sound line sensor, which indeed it must have to avoid time base errors in the sound track. 

    But again, anyone familiar with older motion picture sound projectors, and even some commercial film transfers knows the characteristic "sound" of audio wow whether baked into a film sound track, or introduced in the digitisation process. 

    As an aside Roger's little sound module unit which sensed the speed of the film via the flashes of light from the projector's film gate only achieved long term speed synchronisation  when picture scan and sound scan were united on the editing timeline. It could reduce or remove some wow  introduced by playback on a standard film projector but only wow  upstream of the jockey wheel, not downstream of it at the sound head.

     

     

     

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