Repair audio jitter or is it flutter

[John Mathews]

Some time back I had my old super 8 cine films converted to digital but unfortunately some of them had sound but it wasn't included in the digital version. I have dug out my old Cinerex super 8 sound projector, connected the loudspeaker output via a DI box to my pc and recorded the sound. I can hear the sound and there is music but throughout there are regular fast, short interuptions that could be described as distortion but its more of a mechanical effect than anything like clipping or other normal electronic distortion. It sounds like its related to the mechanical noise of the projector. Is there any software that can smooth it out. I guess the other option is to purchase another projector in the hope that it is better - or else does anyone have a good reliable transfer service to re convert the films, this time with sound included.

[Ed Gordon]

Have you tried playing an off the shelf S8 sound film? At this point it could be your film is defective, or the projector is defective, or the sound head on the projector is defective, or your DI box is introducing bad effects.

You should also upload a sample of the bad audio so that others can listen to it and offer suggestions for possible causes.

[Nantawat Kittiwarakul]

Neither me nor anyone else can give definite answer, until the said audio sample is available.

But besides projector's fault, it could also be the camera's fault as well. Most camera would have the microphone placed just next to the camera body - perfect place to pick up its own mechanical noise. To make the matter worse some would have microphone AGC on by default. Therefore when shooting in quiet place its agc will further amplify microphone's input, making the camera's noise even louder. If it's really the case I'm afraid there's nothing much to do, as the noise was already there in the first place.

[Joerg Polzfusz]

Not sure about that Cinerex, but could it also be an incorrect setting? Something like „duoplay“ or „stereo“ activated for a „single channel mono“ movie? Or some „sound on sound“ or „public address“ feature or similar?
-> anyone knows whether the Cinerex has such features?

[Tim Gillett]

It could be as simple as a partial loss of the bottom loop but yes an audio sample would help.