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Author Topic: N00b question about optical sound
Jan Bister
Darth 8mm

Posts: 2629
From: Ohio, USA
Registered: Jan 2005

- posted February 03, 2005 11:18 AM      Profile for Jan Bister   Email Jan Bister   Send New Private Message       Edit/Delete Post 
I've never had anything to do with the 16mm format... and in the same vein, know little about optical sound (other than how it works).

Just what is the average quality of 16mm optical sound? I seem to have heard that it's generally inferior to magnetic sound although the relatively high running speed of 16mm film (compared to the occasional, rare super-8 optical sound film) allows for a decent frequency range to be reproduced. But what about dynamics - that is, signal/noise ratio? Pops, hisses, clicks? What tendency is there for harmonic distortion/cleanliness of sound and its adequacy to reproduce music in high quality?

I know I'm getting technical here but really am looking for detailed answers [Cool] I happen to be very knowledgeable about any other recording technology (vinyl, tape, compact discs and other digital sound - heck, even AM and FM radio)... but as I'm faced with the decision of possibly buying my very first 16mm feature film, a copy of Young Einstein, I want to make sure I don't get disappointed with the sound quality. [Smile]

Mind you, I don't even own a 16mm projector yet, but that's for another future topic to deal with. [Big Grin]

EDIT

As usual, I remembered more questions the moment I submitted this post, in regard to the 16mm format itself. From what I understand, optical sound is the most common sound format although 16mm magnetic-sound film does exist. Do 16mm optical features normally have two sound tracks for stereo sound, or is monaural more common? Also, am I correct in assuming that 16mm silent film with no sound track may - but does not have to - have perforation holes on both edges of the film? In general, are there any other "configuration" pitfalls to watch out for?

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Call me Phoenix. *dusts off the ashes*

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John Whittle
Jedi Master Film Handler

Posts: 791
From: Northridge, CA USA
Registered: Jun 2003

- posted February 03, 2005 07:48 PM      Profile for John Whittle   Email John Whittle       Edit/Delete Post 
Ok,
1. 16mm silent film may be either single or double perforated film, however there are some 16mm silent projectors that can only project double perforated film since they have sprockets that engage either both sides or use a claw with a pull down in the inside (sound) position.

2. 16mm magnetic sound prints still exist although it's difficult to find anyone to stripe film anymore (at least in the US). All 16mm composite mag prints are mono. I think the top freqency according to smpte specs was about 12K.

3. 16mm optical is the most common type of print and there are two basic sound tracks, variable density (looks like varying gray areas on the the track) and variable area (squiggly lines).

The variable density dates back to the Western Electric days and basically was phased out in the mid to late 1960s. The variable area tracks were originally produced by the RCA Photophone system which used a mirror and a galvo to modulate the track. Various track configurations were produced with different masks in the recorder and thus a dual bilateral track is NOT STEREO but mono. While it would be possible to produce a 16mm DSVA (Dolby Stereo Variable Area) track there are currently no such recorders and a reduction print wuold be necessary. Since there is no commercial market for such prints I don't know of any that have been produced outside of experimental tracks back in the mid 1970s.

16mm optical sound track have several limiting factors: resolving power of the film, film speed past the sensor, printer slip in printing the negative to the positive print to name just three. There is also the problem of image spread in printing negative to positive which results in filling in of high frequency peaks.

Distortion is also a problem as well as dynamic range. 16mm tracks are heavily compressed and GENERALLY will peak out at about 5K. There are better tracks that may reach 7K or 9K but they are rare. Bathtub dupes of PD titles generally will peak out at 3K.

Hiss and pops are problems. Hiss from pick up systems and pops from dirt on the film. There are electronic boxes which will attack those problems but you aren't going to get sound like you will in a theatre running a digital 5.1 or DTS system.

Also it's technically possible to produce a DTS system for 16mm since the time code can be recorded in place of the 16mm optical track and be used to decode and drive the DTS CD. This is available from DTS and I believe has been used in a few presentations. For that matter for presentations you could lock the 16mm projector to a 35mm magnetic dubber and use that for higher quality sound.

As for the hobby collector, you take what you get and that's 16mm with optical sound and it's mono and about AM radio quality.

John

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Michael De Angelis
Phenomenal Film Handler

Posts: 1261
From: USA
Registered: Jul 2003

- posted February 03, 2005 10:01 PM      Profile for Michael De Angelis   Email Michael De Angelis   Send New Private Message       Edit/Delete Post 
Hi John,

I enjoyed the insight on 16mm optical sound, and always wondered about the quality that blasts from that narrow track because I have some 16 prints with wonderful rich sound, some Ok, and some that are awful.

On a Blackhawk print of Bohemian Girl, the print which I own seems to have a lab splice during the second twenty minute section of the reel, and in that last part of the film, the sound does not just go up, but it becomes extraordinarily bell clear.

It leaves me with the impression, that the sound engineers of that era, truly understood recording techniques and were able to achieve high quality standards during the early days of sound.

Likewise I have a collector friend that acquired a 16mm kinescope of a 15 minute Perry Como Program, which was aired on CBS during the early 50's
Along with a graphic equalizer and pre amp, this short film, blows away anything which I had ever heard on 16. It even sounds like an excellent Compact Disc.
What gives with these rare prints, are they apparently the exception to the norm?
I'm not bragging, just thought that you can shed more light in this area.?

Best,
Michael

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Isn't it great that we can all communicate about this great
hobby that we love!

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Jan Bister
Darth 8mm

Posts: 2629
From: Ohio, USA
Registered: Jan 2005

- posted February 03, 2005 10:50 PM      Profile for Jan Bister   Email Jan Bister   Send New Private Message       Edit/Delete Post 
John,

thanks for your very informative reply. Hmm, it actually sounds downright depressing. Am I to understand that 16mm collectors generally can enjoy a sharper picture due to the larger frame size but at the same time have to live with poor sound (compared to super-8 film)?

It sure sounds like super-8 magnetic sound film, regardless of whether it's monaural or stereo, has a definitive edge!

As I have a very critical ear for sound quality, I'm beginning to wonder whether I should just let the "Young Einstein" print go since there's quite some great music in that film. I absolutely love the song that plays during the end credits, it's by Icehouse and it's called "Great Southern Land" [Smile]

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Call me Phoenix. *dusts off the ashes*

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David Michael Leugers
Master Film Handler

Posts: 264
From: Fairfield, OH, USA
Registered: Feb 2004

- posted February 05, 2005 06:27 PM      Profile for David Michael Leugers   Email David Michael Leugers   Send New Private Message       Edit/Delete Post 
Specifications aside, I am amazed at times just how good 16mm optical sound actually can sound. I find that JAN, Victor and other top quality tube amp projectors generally produce very pleasing sound even it is in mono. The greatest majority of
8 and S-8mm projectors have magnetic sound is mono. Mostly
to my deaf ears music sounds fuller with obviously better highs on magnetic S-8mm prints than optical 16mm prints, but dialogue the difference can be hard to judge, for me at least. I know the JAN projector with tube amp outputting to the special JAN external speaker (tweeked to provide optimum playback for 16mm optical sound) can be very pleasing.

David

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Live Free or Die

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John Whittle
Jedi Master Film Handler

Posts: 791
From: Northridge, CA USA
Registered: Jun 2003

- posted February 06, 2005 12:39 PM      Profile for John Whittle   Email John Whittle       Edit/Delete Post 
While the Super8 magnetic sound has an edge in signal to noise ratio and a bit better dynamic range, the slow speed and narrow track are still a tough engineering problem.

Optical sound sufferes from some unique problems. You cannot overload the track there is nothing more than 100% modulation since you'd be off the film so it's just clipped. Area track clip badly (that's all that's produced anymore) and denisty tracks overload softly (like old tube amps).

Time was also a real problem. 16mm sound could have been much better if it was still viable as a commerical entity and we had applied dbx to it to increase dynamic range and noise reduction. It would have theoretically also been possible to do Dolby SVA tracks but again the narrow track and slow speed would have been an uphill battle for noise and output level.

Motion picture sound engineers from the 1930s onwards have always tailored the recording to the track and the theare, even music was orchestrated to match the frequency reponse of the system (the same was true of early 78 rpm records by the way).

A 16mm track from a good negative made on a good printer and recorded to the proper gamma and printed according to a good cross-mod test will result in an excellent track. Also most 16mm sound projectors can be tweaked to reproduce up to 9k. The problem with doing this is it is necessary to refocus the sound optics. Most projectors have the focus set back so they will reproduce both A wind and B wind prints. Since the emulsion is on opposite sides of the film you have to set the optics for a compromise. Kodak and a few others offered projectors with user adjustable sound optic adjustment (on the Kodak its a "fidelity" lever).

If you fully tweak out a 16mm projector with a good print, it'll beat out a Super8 sound print--but then there are the politics of those "true believers" to deal with as well.

John

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Jan Bister
Darth 8mm

Posts: 2629
From: Ohio, USA
Registered: Jan 2005

- posted February 06, 2005 03:44 PM      Profile for Jan Bister   Email Jan Bister   Send New Private Message       Edit/Delete Post 
I've actually wondered - and sorry for veering off the 16mm nature of this forum for a moment here - why super-8 magnetic soundtracks max out at a relatively modest 10kHz (on average) using 24fps and a quality sound projector. After all, super-8 still runs considerably faster (almost 2x as fast) as the good old hi-fi cassette tape, and cassette tape decks have achieved amazing quality which eventually rivaled (and made obsolete) consumer-grade reel-to-reel tape recorders. We're talking an easy 30Hz-15kHz and maybe 57dB dynamic range (using standard IEC-I tape and no Dolby NR) here.

I wonder what would happen if you put an IEC-II (CrO2) tape strip on a super-8 film. [Big Grin]

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Call me Phoenix. *dusts off the ashes*

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Jack Honeycutt
Junior
Posts: 2
From: Portland, Oregon, USA
Registered: Feb 2004

- posted February 10, 2005 06:06 PM      Profile for Jack Honeycutt   Author's Homepage   Email Jack Honeycutt   Send New Private Message       Edit/Delete Post 
I am enjoying this thread. I have a old Auricon Cinevoice camera & it's companion amp. The Auricon will burn in a optical sound track. I am about ready to test my system out. I was going to try some Fomapan, and then maybe some K-40. Do I need to tell the folks that develop my film anything special being that I have a optical sound track? I use Forde for processing.

I would like to learn more about older tube projectors that have good sound output. Can someone post a URL so I can learn more? I have a run of the mill B&H 1585 projector and would like to tweak the audio. Any tips? Can I just play a movie & adjust the sound until I like it? I won't put anything out of alinement will I?

Someplace I have a Auricon document that has the freq responce of it's optical sound track. I'll try to dig it up and post it.

I am excited about shooting some optical sound! I just don't know very much about it. Any tips are more than welcome.

Jack

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Portland, Oregon USA
Canon 1014XL-S
Work Printer Jr
Mac & XP Pro

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John Whittle
Jedi Master Film Handler

Posts: 791
From: Northridge, CA USA
Registered: Jun 2003

- posted February 11, 2005 03:00 PM      Profile for John Whittle   Email John Whittle       Edit/Delete Post 
There isn't much a lab will do now days with single system optical sound. At one time, processors had applicators for color film but it was never available for Kodachome. It will produce a dye track that may reproduce with very low volume depending on the spectral response of your pick up. Old tube amps are really bad about this (such a Technicolor blue tracks) since they peak in the infared region and the dyes do not block any infared light.

Black and white will be pretty good, there are several versions of Auricon tracks, unilateral area, unilateral area with shuttered noise reduction and density. The most common Cinevoice version was the unilateral and an unmodulated track would be 50 percent clear and 50 percent black.

Shot a short test of ten feet or so and have the lab measure the density for you. Alternatively (and this may be in the camera manual) record a track and read out load the exposure setting as you increase the lamp exposure and then in playback in your project see what sounds the best and loudest.

John

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Simon Wyss
Film Handler

Posts: 78
From: Äsch, Switzerland
Registered: Apr 2009

- posted June 04, 2009 05:24 AM      Profile for Simon Wyss   Email Simon Wyss   Send New Private Message       Edit/Delete Post 
Jan, I happen to have produced fresh variable-density sound records on black-and-white 16mm film at our lab. In 2005 we had a new light syringe together with its appropriate electronic control. Frequency response is linear from Zero to 100 kHz. I made tests on Eastman 7360, 7302, and Gigabitfilm. There is nothing with the international standards that would bar one from making tracks on 16mm film as wide as on 35mm stock, so the only difference remains in the length passing by per second. It is fantastic what is possible with an .1" track. 12 kHz can be achieved without problems. Like already mentioned printing may afflict that quality. There's the rub.

By the way, the Kerr cell is still a most viable modulator.

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David Pannell
Phenomenal Film Handler

Posts: 1072
From: Horsham, West Sussex, UK
Registered: Nov 2004

- posted June 04, 2009 07:13 AM      Profile for David Pannell   Author's Homepage     Send New Private Message       Edit/Delete Post 
To tweak or not to tweak; that is the question.

As many Forum members will know, I am fortunate enough to own a few Ampro 16mm projectors with valve amplifiers. What superb machines! [Big Grin]

I also happen to know that David Whistler (see the thread on standard 8 optical sound) is also an Ampro enthusiast with probably more working knowledge of these machines that any one else I know, - hence my prior acquaintance with him.

Anyway, through David, I managed to obtain some 16mm SMPTE (Society of Motion Picture & Television Engineers) standard test films for sound alignment, including buzz tracks, azimuth adjustment, etc. etc.

Having carried out these various adjustments, using an oscilloscope, the improvement in the sound was absolutely unbelievable.

These adjustments are extremely critical, and it is all too easy to 'lose the plot' or in this case, the signal altogether without the proper test equipment, - so if you do have access to some test film and a 'scope, I highly recommend it, - but don't try it without, as you may find it virtually impossible to get the sound back again. [Eek!]

Just some thoughts on my personal experience.

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Dave.

Valves and celluloid - a great combination!
Early technology rules OK!

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John Whittle
Jedi Master Film Handler

Posts: 791
From: Northridge, CA USA
Registered: Jun 2003

- posted June 04, 2009 08:36 AM      Profile for John Whittle   Email John Whittle       Edit/Delete Post 
One point on sound track focus/azimuth. The standard 16mm print position is B-wind, however in the "olden" days there were a number of A-wind 16mm sound prints as well. Thus most projectors left the factory with the optics adjusted to favor the B-wind, but still play an acceptable A-wind print. If you adjust the focus to optimize the B-wind print, the sound will improve, but by chance if you have any A-wind Kodachrome sound prints, the sound will be muffled and well down in volume.

Buzz track adjustment is good, but the horizontal track placement is one of the most widely variable part of prints and viewing stuff made over many years, it's darn near impossible to get a perfect alignment and you can often hear motorboarding that you can't adjust out because it's a print down from a 35mm optical track negative.

John

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David Pannell
Phenomenal Film Handler

Posts: 1072
From: Horsham, West Sussex, UK
Registered: Nov 2004

- posted June 04, 2009 08:42 AM      Profile for David Pannell   Author's Homepage     Send New Private Message       Edit/Delete Post 
Thanks for elucidating that point, John.

As with all things technical, there is always a trade-off. Adjustment for the best compromise might be the best solution here, ie. adjust for equal volume with running the test loop one way round, then turn it over and run the other way round. You will need to repeat this several times in order to get the volumes equal. Thus you will get the optical beam focussed exactly in the centre of the thickness of the film. This is where a 'scope is an essential piece of kit.

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Dave.

Valves and celluloid - a great combination!
Early technology rules OK!

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Claus Harding
Phenomenal Film Handler

Posts: 1149
From: Washington DC
Registered: Oct 2006

- posted June 04, 2009 08:44 AM      Profile for Claus Harding   Email Claus Harding   Send New Private Message       Edit/Delete Post 
Just my two cents here....
Being an old-school hi-fi enthusiast to begin with, I just learned to live with the limited high end of 16mm optical tracks, boosting the HF a bit for playback, but I also found that simply adjusting the optical reading lens up and down can be beneficial for a film.

The "sweet spot" allows for a bit of fiddling in that regard, where you will get better highs, up to a point, after which the sound gets dull again (I use Eiki SSls, for reference.)It's just a matter of loosening one little screw partially, and then gently sliding the lens up and down while listening to the track.

So if you have a projector and have never adjusted the height of your optical reader to begin with, that in itself could be in a less than ideal spot, giving you less than you could have.

Claus.

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"Why are there shots of deserts in a scene that's supposed to take place in Belgium during the winter?" (Review of 'Battle of the Bulge'.)

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Gary Crawford
Jedi Master Film Handler

Posts: 979
From: Manassas, VA. USA
Registered: Jun 2003

- posted June 04, 2009 09:01 AM      Profile for Gary Crawford     Send New Private Message       Edit/Delete Post 
That's where my beloved Kodak Pageants do have an edge....they have a focus knob for easy adjustment for sound..and it really does make a HUGE difference ..both in acquiring every bit of high end that's on the track...and in the case of poor dupes, taking a bit of the high hiss out. but I am spoiled now...with the recent Super 8 re-recorded tracks for Star Wars..and Indiana Jones and the Last Crusade, ect. They really make the film come alive.

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