Can Optical Sound be Improved ?

[Melvin England]

I recently purchased a full length feature on 16mm which I understood to have "low sound" prior to purchase. I just thought..... turn up the volume.

However, not only was the volume low, but it was fairly fuzzy. Not clear at all. Is there any way of improving the fuzziness ? For example, I am sure a really good clean wouldn't do any harm. Or is it that the optics are so worn that it cannot be brought back any further ? I have checked other optical films since this one and it is definitely not my machine.

Any comments would be welcome, thank you.

[Evan Samaras]

Hi Melvin,

There are just two things I imagine might help. One is to pick up a DI box, OR tap directly into the solar cell of the projector and bypass its internal amp for the cleanest signal possible. The second thing you can do is to patch into an external EQ to see if you can clean up some of the frequencies. I’m afraid I’ve been in this position, and the sound clean up is never as much as we hope it might be.

[Steve Lee]

Hi Melvin,

A couple of years back I made a module up to hold a laser diode to replace the exciter lamp on my 16mm projector.
I made it so it used the same lamp base as the exciter so it was powered by the projector power supply. So there was no need for any other modifications.

Having worked in the business at the time when 35mm prints went over to use cyan soundtrack, and hearing the difference that a laser made to a standard optical soundtrack, it seemed a no brainer to do the on 16mm or even 8mm.

Because there is no lamp filament to have to align with the slit in the lens assembly. The monochromatic light produced by the laser is of a single wavelength, so as long as the light enters the back of the lens assembly as near as possible straight on it will work.
The benefits of using this gives a greater volume and a greater frequency response to the soundtrack.

[Nantawat Kittiwarakul]

If the issue is only on that particular print I then suspect it's in fact the lab's fault (during printing, or developing, or both). In some cases there's little to nothing you can do to that.

I once had a very faded Eastman print with not just VERY low volume, but so scratched up that the audio was completely inaudible - just cracks & pops.😩 Upon close inspection I've found that the audio track was just as badly faded as the image, which it definitely wasn't supposed to be - the audio track should remain dense & contrastly no matter how badly image had faded. The only explanation is that the lab somehow FORGOT to re-develop the track to add back the silver, thus the audio would be pretty low even when new. Adding the loss of the dye and lots of wear & tear from use to the mix, and now the audio is completely gone.

[Ed Gordon]

The original soundtrack can be restored on a new print, but there does not appear to be any way to "revive" your print.

[Melvin England]

Thank you everybody so far for your replies. Sadly, I am not a technical person so any adjustments to the sound mechanism would only end in complete disaster for me.
It looks like I am going to have to accept that I bought a bit of a dud on this occasion. Pity really, as it was a great Humphrey Bogart film which I fortunately also have the 4x 400' version on super 8. Plus it was only £20 so it wasn't megabucks !

[Steve Klare]

The problem you run into with a low audio signal is that when you boost the volume setting to bring the signal up, you also amplify all the nasties that were there all along and normally of no trouble. On other prints with stronger soundtracks their signal is loud enough that their signal/noise ratio is high enough that things like power supply hum and hiss and stray pickup are way down in the dirt and you might not even notice them.

The thing is there isn't a lot to be done about this: the audio systems are operating up to normal spec: they simply need a good signal in the first place to get pleasing results.

On my own system, if I have the volume settings at their normal levels with no film in the machines, the speakers are either silent or very close. If I crank the volume up enough (still without film), I get audible noise: the exact same noise that gets mixed into my audio tracks if I have to set the volume very high due to the track.

(This is actually useful: first thing I do after I have everything turned on is crank the volume way up: if I don't hear some hum and hiss, either something isn't connected or something is actually still turned off!)

[Juergen Kellermann]

The film might be a dupe, as low, muddy or scratchy sound often happens in these prints. There is nothing that can be done about it. You can try and change some settings in the amplifier, e.g. with an equalizer. But in the end, a soundtrack that is dupey or not printed properly can't really be improved much.