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Author Topic: What are the sound formats on 16mm film? Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 12-07-2002 12:07 PM                     O.k. folks, a few more tracks. This is a duplex track. It is not a negative of a bilateral track. It would be more correct to think of it as two unilateral tracks facing in opposite directions. Another way to get two modulated edges. These tracks were quite common, on both 35 and 16mm, into the '70s. This sample is from 'Basic Oxygen Steelmaking'. Technicolor print with silver track. I have seen a picture of an early Dolby Stereo track which had two unilateral tracks facing in the same direction (duo-unilateral?) Everybody here must have seen this one; a duo-bilateral track. Four modulated edges. This Eastmancolor print is about the same age as the electrostatic copying one. The difference is obvious; the reason is unknown. As early as the mid '30s experiments were being done with using the two tracks separately for two channel stereo. Of course, this eventually developed into the Dolby stereo tracks of today. Another variant of this track was one form of push-pull track. In this, the modulation of one half of the track was opposite to that of the other; one would be wide where the other was narrow. There were other forms of push-pull tracks, a variable density one, where one half was light where the other was dark, and a variation of the duplex track, where the black central area was of constant width, but moved from side to side, the clear areas on either side of it forming the two inverted tracks. This was the so called 'snake' track, four of which were used for Fantasound. I suppose this would have to be described as duo-duplex, but I've never heard the term, and this is the only example I've ever seen. The track had been partly covered by a half width magnetic stripe, but this carried only the narration, not the music, and was therefore blank at this point. I was therefore able to remove a small area of stripe, to reveal the full track, and afterwards replace the oxide, returning the print to its original state. If two edges were better than one, and four were (possibly) better than two, somebody had to go one (or eight) better (or worse). This is the Mauer track which started this whole thing. Again, this example had been half covered by stripe. If they awarded an Oscar for the most interesting film, 'Principles of Rotary Air Drilling' would be unlikely to win it. The track is silver, but note the very low optical density. Was it deliberately under exposed and developed to minimise the risk of the very narrow lines being totally oblitterated? Whatever the reason, the sound quality is, as might be expected, poor. Anybody know the reason for those strange patches of picture to the left of each frame? Due to the low resolution that I had to use for these pictures, these very narrow bias lines do not reproduce well on screen. The first picture in my previous post was a small area cropped from the original high resolution of this picture, with the contrast increased. We have now reached twelve modulated edges, and things are starting to get a bit silly. There would obviously be no reason to go any further, and therefore nobody would bother to produce this: I doubt that the details of this track will be visible on screen from this scan, and in this case I was not able to remove the stripe covering half of it, as it carried the full mix of the soundtrack, and therefore carried sound wherever the optical track was modulated, but this track really does have eight bias lines, sixteen modulated edges. It is difficult to see what possible advantage this could have. This track actually starts to look quite similat to a variable density one, so we are almost back to where we started. The last three of these tracks I have only seen on 16mm, all the rest I have also seen on 35mm. The duo-bilateral track was in use in the '30s, and variable density tracks were still being recorded in the '50s, possibly into the '60s, so there was a period of several decades while most or all of these tracks were in use concurrently. I will stop at this point, before I fill Brad's servers with pictures. For anybody who is interested, the BKSTS produce an excellent wallchart, featuring many more types of tracks than I have shown here, and Robert Gitt does a very interesting lecture on the subject, which I was luckly enough to be able to attend at the National Film Theatre a few years ago.  |  IP: Logged Leo Enticknap Film God Posts: 7474 From: Loma Linda, CA Registered: Jul 2000 posted 12-07-2002 04:04 PM                        quote: Anybody know the reason for those strange patches of picture to the left of each frame? They are a camera aperture identification mark. Some models of 16mm and standard 8mm camera had small apertures with a distinctive shape between perforations, which were exposed along with the main frame. These marks can be used to identify the make and model of camera which shot the footage. I have an identification chart of them somewhere which was compiled by Harold Brown (formerly head of preservation at what was then the National Film Archive). For obvious reasons these charts are usually found on reversal originals (e.g. home movies): they won't be reproduced by anything other than continuous contact printing. In your example, continuous contact printing must have been used for every generation from camera original to release print.  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 12-08-2002 11:55 AM                        I had once heard an explanation of why multiple tracks were used in 16mm, even though they were all mono duplicates. I will say up front that I don't know the veracity of this explanation, only that I heard it years ago when I questioned those 6 tracks on a print of one of the Bell Science series films (HEMO THE MAGNIFICENT, maybe). Perhaps someone else here can comment on it. I was told that the reason for smaller, multiple tracks on 16mm instead of one larger one is that the use of multiple tracks minimize the effects of azimuth misalignment. If the slit has an angle of error from the soundtrack perpendicular, the degree of that error will be smaller as it intersects the smaller tracks than it would be of a larger, single track. My question is, even though the error is smaller at the intersection of each of the multiple tracks, why is the error not cumulative and result in the same total error as the single track. I guess should have paid more attention in Geometry. Frank  |  IP: Logged Michael Brown Phenomenal Film Handler Posts: 1522 From: Bradford, England Registered: May 2001 posted 12-16-2002 04:35 PM                     OK. On my 16mm projectors the outputs are 8 ohm 1/4 inch. So... EDIT: What the?? I just made a new post to this thread, so why has it not been brought to page 1???  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 12-16-2002 05:33 PM                     Michael, these sound (no pun intended) like speaker outputs from a built-in amplifier. Many protable projectors had no other output, and need to be modified to feed them into a theatre sound system. Are these ELF (EIKI) projectors? They were probably the most common to use quarter inch jack sockets, but there were others, Graflex (Singer) for example. Bell and Howell used a modified DIN plug for their later (1960s onwards) projectors, and a two flat pin, one wider than the other, plug on the older models. Are they portable or fixed machines? Others have written that some models of ELF projectors can provide a line output to an external amplifier from the ring of a three pole stereo jack plug, with the speaker output on the tip. I've never seen this, and I don't know which models might be so equipped. Most fixed, floor-standing machines, intended for use in a large auditorium provide a 600 Ohm balanced line output, but some provide an output direct from the photocell and magnetic heads for connection to external pre-amps, as with 35mm. Neither of these would be 8 Ohm, so I'm pretty sure that what you have is a speaker output.  |  IP: Logged Jeff Taylor Jedi Master Film Handler Posts: 601 From: Chatham, NJ/East Hampton, NY Registered: Apr 2000 posted 12-17-2002 03:17 PM                     I can't speak for the British equivalent Elf machines, but the later US Eiki 16mm portables (halogen and xenon) have a dual output scheme which includes 8 ohm from the amp, and 600 ohm balanced from the preamp (yes, it is affected by the volume, bass, and treble controls). The 1/4" jack is really a stereo jack, and you pull the 600 ohm off the ground and the second "tip" of the jack. For those who want to get serious, you can also pull directly from the solar cell by disconnecting the two pin plug with this signal from the amp board.  |  IP: Logged William Hooper Phenomenal Film Handler Posts: 1879 From: Mobile, AL USA Registered: Jun 99 posted 12-20-2002 06:32 AM                        I've run 16mm theatrically only once, but if I ever must again, I will send the audio through a noise gate then an Aphex Aural Exciter. As has been mentioned, the Fi on 16mm can be less than Hi. Early Aural Exciters can now be picked up cheaply used from eBay, studio & broadcast equipment resellers. The sort of overly crisp Aural Exciter sound is not my favorite in production, but it would be perfect for 16mm in auditoria which tend to be tubby or boomy anyway.  |  IP: Logged Michael Brown Phenomenal Film Handler Posts: 1522 From: Bradford, England Registered: May 2001 posted 12-20-2002 11:48 AM                     Yes ELF projectors. So all I have to do is find out where the other output it.  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 12-23-2002 05:15 PM                        The Aphex Aural Exciter is a great tool and we use it on both our 16mm channel and also the 35mm center channel -- our theatre is a big single screen (2500 seats) and although we did a lot of acoustic treatment of the room to improve speech intelligbility, I was not not 100% happy with it the results. Adding the Aural Exciter did wonders to clear up center channel dialogue. Now I won't run anything without it. We also use a JoeMeek preamp for the 16mm track with the output of the solar cell going directly into the preamp. The sound of that piece of equipment is day and night above the cheap mic preamp that was originally installed when the projector was converted from phototube to solar cell. We are lucky in that we have two recording studios in our performing arts complex so I get to play with gear designed for the pro-audio field but which can be great black box tools to use in the booth. The JoeMeek preamp and the Aphex are examples. We also use a dbx bass enhancement unit as well as an Orban Stereo Genarator (naturally it's not real stereo but it does a nice job of spreading the signal out a bit across the screen -- anything to help the lowly 16mm track). Frank  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 12-24-2002 10:57 AM                     Michael wrote: quote: So all I have to do is find out where the other output it. Michael, I used to run Elf projectors when I was an AV technician. We had the old blue ones with the separate motor an lamp switches, and the small flap which you flipped down to run and up to rewind, took an EJL 200W lamp, also the later blue ones, single rotary switch, larger flap, which worked the other way - down to rewind, and ELC A1/252 250W lamp. Then there were the later still black ones, NT-1 I think, similar but autoload, we always laced them manually. Lastly we had a portable (with difficulty) dark brown Elf-Lite EX-1500 xenon. I never used the later light brown slimline lightweight ones. I am certain that some of the machines I used did not have a line output. I have never seen it, but it is possible that some of the machines I used had it without me being aware. I'm not sure if it is the case that the American machines had it, but the British ones did not, or that the later ones had it, but the earlier ones did not. Open up the case of one of your machines and have a look at the connections to the speaker socket. If there are only two wires then you do not have a line output. If there are three wires then you probably do. In this case make up a cable with a headphone type quarter inch stereo jack plug on one end, and whatever you need to fit your sound system on the other. At the projector end, connect to the sleeve and ring of the plug only, do not connect to the tip, this is the speaker output. Since there are only two contacts available on the socket, other than the tip used for the speaker output, the line output must be unbalanced. If your sound system has balanced line inputs (do not use mic inputs) they will probably be on three pin XLR connectors. These have the signal on pins 2 and 3, and the screen on pin 1. In this case, try joining pins 1 and 3, and connecting the screen to that, with the signal going to pin 2. Without knowing the spec of the projector output and the input you will be connecting to, I cannot say if you will need a matching transformer, or other components. Try it, with the volume on the amplifier turned right down, then turn it up slightly, and see what it sounds like. If it is very load and distorted, then you are overloading the input. Portable 16mm projectors were not good at providing line outputs for some reason, most of those that do not have one can be modified fairly easily, but exactly where you tap off the signal, and what extra components you need to add to get a signal of the required level and impeadance will vary from one model to another. Hope this helps, Stephen.  |  IP: Logged Jeff Taylor Jedi Master Film Handler Posts: 601 From: Chatham, NJ/East Hampton, NY Registered: Apr 2000 posted 12-24-2002 11:50 AM                     Stephen is right; you can go from unbalanced to balanced by jumping the two pins of the xlr with no ill effects. I've done it. Surprisingly, it actually doens't make a heck of a lot of difference on the Elf/Eiki's whether you actually use the speaker or unbalanced line out in terms of sound quality. One caution, however. They're notorious for ground loop hum. If you run into it Radio Shack in the states has little stereo isolation transformers for around $20. I assume there's something similar in the UK.  |  IP: Logged Lindsay Morris Expert Film Handler Posts: 233 From: Darlington, WA, Australia Registered: Sep 2002 posted 12-25-2002 07:23 AM                     Micheal, When not runing the 35mm outdoor site I do a lot of 16mm "portable" shows for local groups. As every show is different I have a range of 16mm machines to utilise ranging from Eiki SL1 (250watt halogen lamp) a bigger Eiki with a 500 watt Xenon and my old favorite the Bell & Howell 666 with a Marc 300watt lamp. All machines except the Xenon Eiki only have speaker output so I have standardised on using a 10k -10k line transformer mounted up in a 35mm still film plastic case (pill box looking thing with a snap on lid) and a suitable plug to fit either Eiki and the B&H which uses a crude looking Din socket and a rather rare plug that fits it. With this arrangement there is no ground loop problems, no possibility of upsetting the projector amp (there is a slight DC component at the speaker socket on almost all transistorised amps) and a clean signal is then fed into a stereo simulator. The L & R output from that goes into a small mixer for non sync and occasional mic work and the lot is then shot into a 100watt per side stereo amp. This feeds two big beefy speakers with a pair of 300mm drivers in a ported enclosure and a HF horn mounted on top of each unit either side of the screen. We have done outdoor shows for around 800 people onto a 8m screen with this setup and get a lot of very favorable comment regarding sound quality. The 10k - 10k may not be strictly theoretically correct but it does work. The projector runs on about 2 or 3 on a scale of 10 on the vol control and what comes out is a reasonable match into a solid state device after the projector so you do not loose the highs. The line transformers in Australia cost around $9 each and I would imagine that something similar is available in UK. I have used the same setup on other 16mm machines such as Hokushin, Singer, Fumeo and Elmo with equally good results all round and in one case hired a B&H 666 to a local cinema for a weeks screening of some Gospel films and the tranny just went straight into their Non Sync input with brilliant results. The Xenon Eiki does have a 600 ohm line output but using that seems to drag the highs down quite a bit and the only time I use that is if I use the big Eiki at the outdoor. There I have valve amps so have setup a 600 ohm to 100k ohm line input just to suit the Eiki/valve amp combo and that works fine as well. For continuos shows we use 6000' spools and an ELF long play unit which seems to accomodate just about any sort of 16mm machine. There it is, a simple almost "universal fix it" for getting 16mm signals into bigger sound systems. Lindsay  |  IP: Logged Michael Brown Phenomenal Film Handler Posts: 1522 From: Bradford, England Registered: May 2001 posted 02-21-2003 03:52 PM                     More dumb 16mm questions: How are 16mm films shipped? Is it all on one reel? Is it multiple reels that need splicing as you do with 35mm? If so can you load a whole feature on a projector at once? In other words. I know nothing about 16mm. Help! Please!  |  IP: Logged Bill Gabel Film God Posts: 3873 From: Technicolor / Postworks NY, USA Registered: Jan 2002 posted 02-21-2003 04:00 PM                     Most 16mm films are shipped on 1600 foot reels. A 2 hour show would be on 3 Reels. Yes, you can splice them like a 35mm show on to a big reel.  |  IP: Logged Stephen Furley Film God Posts: 3059 From: Coulsdon, Croydon, England Registered: May 2002 posted 02-21-2003 04:42 PM                     16oo feet of 16mm is equal to 4000 feet of 35mm. Most fixed projectors, at least the more modern ones, can take up to 6000 foot spools, most portable ones are limited to 2000 feet, but you can get long run attachments, often just a pair of long spool arms, fixed to a baseboard, between which sits the projector. This is more or less the equivilent of a tower with 35mm. Platters are not normally used for 16mm, but it has been done, there are some pictures on the film-tech site, or you can use two machines, and do changeovers, as with 35mm. Unlike 35mm, which in the UK is normally delivered on cores, 16mm usually comes on spools, for features these are packed in a box, without cans. For shorts, the spool normally comes in a can. Unlike 35mm, where 5/16" 9mm 3/8" and 1/2" spindles can be found, sometimes with more than one keyway or driving pin position, and a few odd machines, e.g. BTH SUPA, which took totally non-standard spools, 16mm ones are universal, the shaft is 5/16" diameter, but the few milimeters nearest the machine is enlarged to a 5/16" square. Most spools have a square hole on both sides, but a few have a round hole on one side, so they will only fit one way round. All spools also have a keyway, and will fit on a 5/16" 35mm rewinder.  |  IP: Logged

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