8mm Forum: Silent speed vs. sound speed

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Posted by David Pannell (Member # 300) on April 07, 2005, 11:10 AM:

Let me throw this open to all,

With regard to Super 8 sound film cartridges, of which I have loads still in the freezer, is it recommended to shoot at 18fps or 24fps? Does the 24fps help to eliminate the sound jitter, or is there really little difference? Up to now I have been using 18fps, simply to save on film, as there’s obviously a 25% saving to be made – or is this false economy?

When compared to a tape recorder, the 18fps represents a speed slightly slower than the 3-3/4ips, whilst the 24fps would be slightly quicker than this. So it is unlikely that there would be much improvement in actual sound quality. You have to virtually double the speed of magnetic audio tape to get any appreciable improvement – frequency response etc.

Any thoughts or discussion on this subject would be gratefully received.

Thank you.

Dave.

Posted by Steve Klare (Member # 12) on April 07, 2005, 11:52 AM:

I'm not sure about the merits of 24 FPS for added sound quality (I've often heard they are negligable), but I've noticed a different factor recently that's got me thinking about trying it on my next film project.

I just went to a much larger screen and I've noticed a distinct blur of motion (especially when panning) in my 18FPS films that I didn't see on the smaller screen. If for example the camera and or subject is still at the beginning of a scene and then moves quickly, the apparent sharpness drops way off with the movement.

I will say this much for 18FPS as far as sound goes. The projectors do run more quietly. You'd think some part of the improvement in audio quality would be drowned out by the machine pounding away at 24 FPS (...guess I need a projection booth!).

Posted by David Pannell (Member # 300) on April 07, 2005, 12:35 PM:

Hi Steve,

I know exactly what you mean about the panning. When shooting Regular 8 or Super 8 (silent, of course) I always pan at 24fps, then switch back to the 16fps (reg 8) or 18fps (sup 8) for all other types of shots. This has a two-fold advantage.

1. The blurring and any jerkiness is kept to a minimum, and

2. When the whole film is projected at the 16 or 18fps throughout, the panning scenes are extremely smooth, and, although slower, this does not seem to detract from any impact, as the scenes are much clearer.

If the idea of the panning scene is to create blurred jerkiness, then fine to use the slower speed throughout.

But - sound film is a different matter - you can't keep changing the projector speed!!

As you rightly say, projector noise is also a consideration.
Dave.

Posted by Joe Taffis (Member # 4) on April 07, 2005, 05:16 PM:

In my experience shooting a lot of film using both speeds; the picture, sound, and also "transfer to video" qualities are all much better at 24fps...but the quality of your camera equipment, and processing, are also big factors with both picture and sound.

Posted by David Pannell (Member # 300) on April 08, 2005, 12:55 AM:

Thanks Joe,
Transfer to video is not an issue for me, as I intend to keep everything on film. The cameras I use are both Bauers; an S409XL and an S609XL with microprocessor. In your opinion, do these cameras justify 24fps? I use John Schwind for my processing. The other thing is, I don't have a separate projection room, so projector noise at 24fps is a bit of a factor.

In view of the above, would you still think 24fps is worth doing?

Many thanks,

David.

Posted by Tim Christian (Member # 48) on April 08, 2005, 02:11 AM:

I shoot at both 18 and 24 fps and stripe afterwards. Sound quality is about the same. The main difference is in panning - especially in scope. Even with a viscous-damped tripod head, blur or jitter due to camera movement is far less detectable at 24 fps.

Posted by David Pannell (Member # 300) on April 08, 2005, 03:13 AM:

Thanks for your input Tim. Do you find the increased projector noise at 24fps anything of a problem or objectionable at all?

Please, everyone, keep the pros & cons coming.

Thanks,

Dave.

Posted by Jan Bister (Member # 332) on April 08, 2005, 05:05 AM:

I can't say I find increased projector noise at 24fps to be much of an issue - for one thing, of course it depends on the projector itself, there seem to be some that purr like kittens at 24fps (my Bauer T450 is one of those) and others that might as well have their 18fps settings labeled 'earthquake' [Big Grin]

In addition to that... if you watch your film silent, it probably doesn't matter much anyway, but if you add sound to your film, then... well... with a big picture there should be loud, booming sound which will drown out any projector noise anyway, right? [Wink]

Posted by Tim Christian (Member # 48) on April 08, 2005, 06:23 AM:

Projector noise: I use Eumigs and Chinons. Especially with the Chinons, noise is not objectionable at either 18 or 24.

Posted by Jan Bister (Member # 332) on April 08, 2005, 06:28 AM:

Unless the Chinon is an SP-330MV. [Mad]

Posted by Kevin Faulkner (Member # 6) on April 08, 2005, 08:23 AM:

On the Elmo's and I suspect most machines the quoted frequency response is higher on 24 fps over 18 fps. Also background noise (hiss) as well as wow/flutter will be lower. When recording onto stripe 24 fps will give the best dynamic range which is what we should be striving for especially when recording music.

Kev.

Posted by Jan Bister (Member # 332) on April 08, 2005, 03:13 PM:

Kevin is absolutely right on these counts, and he didn't even mention sound dropouts (due to either magnetic stripe damage or splices) will be less noticeable at 24fps as well. [Wink]

Posted by Kevin Faulkner (Member # 6) on April 08, 2005, 04:22 PM:

Yes Jan, good point too.

Kev.

Posted by David Pannell (Member # 300) on April 09, 2005, 12:52 AM:

Thank you everyone for your contributions. It has been most informative and helpful. I guess the only real test for me is to actually give it a try. The general concensus of opinion seems to be that it's a good idea. I just wanted to make sure that it wasn't a complete waste of time and film.

Best to all,

Dave.

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