Once, I got a p-p track print- only I was running a mono system. I ended up putting masking tape on the edge of the lens. That at least got me through.

It's true that just buying a lens for 1.33 would "maintain' backward compatability. But, the same could be said for this issue: If that theater paid to have the regular exciter lamp and solar cell re-installed (probably even cheaper than buying a 1.33 lens) backward compatability is maintained.

As to the question; what are the benefits to the exhibitor and the film goer, you win hands down. As far as I can see, there are none.

But, I wouldn't mind helping labs reduce their cost, even if it is fairly small. Studios and exhibitors are supposed to help each other. Having this 'change-over date' looming before us has given us a chance to pry money from the home office to upgrade older soundheads. They wouldn't part with the money otherwise.

What do you mean by upgrade? If it is to get reverse scan optics, then go for it. I too would take the led with reverse scan optics. In this case, the led is coming along for the ride. I can certainly appreciate your desire to get the reverse scan system (by any means available).

As far as backward compatible, you and I will have to disagree on this one. For me it is a paramount importance.

Steve

First of all, there is no problem getting enough density in the cyan track to keep it quiet---with or without SR. By this I mean the density at 66o nanometers which is where the cyan dye has its peak density and where our LED's have there peak output. However, you can expect increased noise from some of the older formats, but it is not necessarily a function of the red LED. Many years ago I had the misfortune to run some of those damn magenta VD tracks and they were pathetic then and I am sure that they haven't gotten any better. Peoples expectations were a lot lower in those days.

I mentioned that there is another possible noise causing factor. This is that the light emitting from the LED is rather well collimated which means that dirt in the track will be in pretty sharp focus and heard as pops etc. With the old slit lens system there is a lot of diffusion before the light hits the cell and this tends to lessen that type of noise. This is just one of those things we don't like to talk about.

Even by the advocate's admission, the cyan track on a clear day will be at least 2dB noisier than an equivalent applicated track. I don't consider the exisiting optical track to be god's gift to sound, noise wise. Furthermore, the collimated light hitting a scratch or light abbrasion seems to excite SR noise reduction, making it that much worse.

I have been known to take some Scotch "magic" tape and place it over the LED to make it's light more diffuse and less then noise...of course you pay for this in light output.

The manufacturers of the leds may not like to talk about the increased noise but before the industry forces it onto people, it should be addressed. Just look at how much better the leds have gotten since they first came out.

Now if your fine company can come up with a dual light source (say using a fibre optic) such that we can have either white light or red without having to mechanically readjust anything, I'd be excited!

It seems to me now that we perhaps should reconsider the decision to get red light kits to the projectors, or at least wait and see what happens.

On one hand, we play quite a few new features, especially during the annual Göteborg Film Festival, and the cyan dye prints will undoubtedly show up before long. As I understand it, these prints won't work with traditional tungsten soundheads such as ours.

On the other hand, we are normally a revival house and show a lot of old prints, including a number of variable density prints.

So if I understand all of you correctly, we will face trouble no matter how we choose. Am I correct?

The Cyan tracks are not a definate thing. They are a proposed item that still has to go though testing to prove it's worth and still requires industry acceptance. Failing that, they would need some sort of legislation on a worldwide basis to force the issue.

The LED light source does have some advantages over the traditional tungsten filiment exciter lamp. The biggest advantage is that the uniformity of the illumination across the scanning area is more even.

Often associated with the LEDs is the inclusion of "reverse scan" optics, though that isn't always the case (eg the JaxLight by USL). Reverse scan optics dramatically improves frequency response, crosstalk and channel separation.

One thing I am considering for "rep" houses that have Norelco DP-70s is using a combination of JaxLights and Exciter Lamps depending on the show. On some DP-70s, the slit could use to be narrowed a bit though.

Steve

What can you tell me about these LEDs? Are they expensive? Do the require extensive rebuilding of the soundheads? And most importantly, how's the sound (and otherwise) quality? Any known problems?