DIY Frame by Frame Telecine Issue

[Larry Bell]

So what do you do with audio??
I used an old B&H projector and made up a cord to go from the speaker plug to my computer. Played it and recorded it in Audacity.
It's mono but I duplicated the channel in processing.
Still, the audio sounds like crap. It sounds similar through the projector speaker.
Any suggestions in getting some good quality audio?
Thanks!

[Nantawat Kittiwarakul]

LOVE your setup Larry.😍 Seem simple but extremely effective!

[Stan Jelavic]

Larry, noticed that you use a macro lens. What model is that?
For sound you would have to determine if the issue is caused by the film or the pickup or the amp. Can you send a sample of the sound. Do you have any other film with sound to try.

[Larry Bell]

LOVE your setup Larry.😍 Seem simple but extremely effective!

Thanks!

[Larry Bell]

The lens is a 100mm f2.8 Vivitar True Macro (1:1) manual focus lens for Nikon F mount. Here’s a sample with sound, not synced yet.
https://youtu.be/0We0HxiWLLQ
Thanks!

[Stan Jelavic]

That is a good quality lens Larry. That was my point in the discussion earlier. You want to stick with a single good quality lens. Sometimes we get lucky with custom lenses but more often than not we end up with soft images, corner aberrations etc etc. Anyways that is my opinion based on my own 14 year DIY telecine experience.
For good quality lenses the reverse mount also works, see my DSLR thread.
In your case for super 16 your image will cover around 1/2 of the camera screen which I believe is adequate.
This is based on my quick calculations - you can correct me if I am wrong here.

The sound clip does not seem to have any noticeable white noise which was my concern.
I will do the waveform analysis to check for distortions.
BTW - very nice clip...

[Stan Jelavic]

Looked at the audio clip and here are a few findings.
The signal to noise is not very good, my estimate is around 10dB.


The left side shows a sample of the sound and the right side the background noise. The noise is also noticeable in the waveform on the left with the positive and negative jumps.
Assuming that the cause is not in the original recording, some cleaning may help. Perhaps other members with more audio recording experience can pitch in here.
The other distortion can be caused by nonlinearities in the system but that seems unlikely because the sine waves are reproduced pretty nice. So I would rule that form of distortion out.
The frequency response may need some tweaking as well.
Another big issues that I noticed is the pitch change probably caused by speed change. Again, assuming that the original material is OK the possible cause can be the projector motor or worn out belt. I suggest you inspect the drive components for wear and tear.

[Larry Bell]

Thanks Stan. I think I’ll try to record off of my Panoram out of the amp. That could give us an idea if it’s just the projector. I think the media itself is ok. Then narrow it down to what the issue is. I’ll post the audio when I do it. Thank

[Stan Jelavic]

OK Larry. Make sure the playback speed is constant.
I took another look at your audio and some of the noise is around 6000 - 10000 Hz.
Applied a low pass filter.

That seems to clean up some of the noise.

The image on the right is the original.
This is the filtered sound.
https://drive.google.com/file/d/1CQv...ew?usp=sharing
Again the pitch change due to speed change is not corrected here.
If the speed is pretty consistent then a pitch change can be applied to the whole clip.

[Larry Bell]

Thanks Stan, There certainly could be speed changes, it’s an old projector. I’ll have to figure out a way to monitor it. I’m on the road and can’t download the clip but will when I get home. What program are you using to clean up the audio? Maybe I just can’t see the name on my phone! Thanks!

[Stan Jelavic]

I used wavepad free version.

[David Brown]

Hello Larry

Listened to your audio and it sounds over modulated. In a word, too loud.

Be sure to use LINE-IN, and not the Microphone input.


Before worrying about matching impedance s, just turn the source volume down.

Hi Stan! I'm not familiar with Wavepad, but Audacity is also free and it has an audio level meter.

Good luck

PS. Just realized you said the projector sounds as bad. Do you have any way to bypass the projector's amplifier and speaker? If so, connect the sound pickup directly to the microphone input, unless you have another amp.

[Stan Jelavic]

Hi David, good input to Larry. Based on what I saw, there is no clipping in the system but there is a noise at around 8 kHz and the low pass filter seems to clear it out. The other issue that I already mentioned is the speed change which is very annoying. This could be the belt issue. Remember the worn out belt driven turntables and pitch change...but it is worth trying your suggestions as well.
I have not tried Audacity. Does it have sound filters (equalizers, noise reduction, pitch change etc)?
Just checked it and it looks pretty powerful. Will give it a try. Thanks for the input.

[Nantawat Kittiwarakul]

Not 100% certain, but the B&H that Larry used for audio capture seems more or less the same as B&H that I once had (TQIII series).

The main drive motor is of dc type with electronically controlled speed regulation, much like most super8 projector. There are 18/24 fps speed selector on the rear panel, with 2 pots to fine tune the selected speed hidden inside - pretty usual stuff.

And its speed control sucks, really.

The motor's speed would always fluctuate wildly no matter how I adjusted that 2 pots. combined with all other issues I finally gave up and sold it away. This MIGHT involved to the issue Larry is facing with.

[Larry Bell]

Thanks everyone!
It looks like I have a bunch of issues to overcome. This is what I'm going to try...
1. Sound Quality Solution - bypass the projectors internal amp.
2. No Line In Port on My Computer Solution - I just ordered an audio recorder with a line in. I can move this to the projector rather than moving the desktop to the projector.
3. Speed Change Issue - I just ordered a laser tachometer so I can verify the speed issue. Not sure how I will overcome it yet, but I will.
I'd like to get the best quality audio recorded directly so the starting point in post is as good as possible. This will take me a few days. Will post the new results. Thanks again for the help!