scanner options?

[cipher0]

OK then please tell me the specs of the EMS-8000 and Pangolin scanner so i know if i like them and they can fit in my case and also the prices.
I tried googling with no results. Thanks.

call justin at pangolin. you can order right now

Ordr or preorder? I didnt expect them to make it so fast, good to know.

[cipher0]

Looks like the Pangolin scanner is 30K. Is there any 40K or 60K from Cambridge, Eyemagic or Pangolin?
I know the scan angle of pangolin is going to be higher than DT, but i've found out that doesn't mean you can have 40K at lower angle.

[Pangolin]

INEXPENSIVE, HIGH QUALITY SCANNERS

We have prototype quantities of Compact 506 that have been released to a few companies and a few individuals on PL. This is the least expensive scanner we make, and although prices for individuals buying a single piece haven't been released yet, these are designed to be priced where most Chinese scanners are.

30K IS THE ONLY TRUE STANDARD (with 60K being an alternative, interim standard)

The Compact 506 was designed to be a 30K scanner. It will go faster, but it was designed to go 30K. And don't forget, 30K is the standard, and actually (aside from 12K) the only real ILDA standard. Other than that, 60K was a standard proposed as an interim standard in my final years as Technical Committee Chairman of ILDA, but it was never finalized. Nevertheless, I consider there to be only two true standards -- 30K and 60K. Anything else is non-standard...

If you have a few moments, I'd like to you watch a presentation that I gave at the last ILDA meeting. It discusses a few important topics for scanners -- namely heat generated while scanning, and also the quality of the projected images. You can see the video here:
http://www.youtube.com/watch?v=BiaM0adidIo

SCANNERS ARE DESIGNED...

One thing that I hope you can realize is that scanners are DESIGNED to go a certain speed. Our least expensive scanners are designed to go 30K. Likewise, the original Cambridge model 6800 was actually designed to be a 30K scanner. The reason why I talk about "the original Cambridge model 6800" is because substantially ALL CHINESE SCANNERS ARE ESSENTIALLY A COPY OF THE ORIGINAL CAMBRIDGE MODEL 6800. The reason why they're a copy is because Cambridge did not patent the ORIGINAL model 6800, but did patent the improved version, and also did patent all of their newer developments such as the 62xx series. What this means is that EVERYONE WHO COPIED THE ORIGINAL CAMBRIDGE MODEL 6800 IS STUCK IN 1992, since that scanner was introduced in 1992. This is 1992, 30K technology, that is all.

HIGHER PERFORMANCE IN ONE AREA MEANS SACRIFICE SOMEWHERE ELSE

Claims of scanners that LOOK like a 6800 going faster are either bogus, or more often tuning to faster-than-30K-speeds will sacrifice performance somewhere else. At some point soon I will produce a video, showing the QUALITY of the projected images that come from DT40 scanners (which I consider to be 30K scanners tuned to 40K). If you look closely, you will see that the projected images have distortions, ringing, and other artifacts. (If that's not important to you, then that's the sacrifice you make...)

Also, as discussed in my video, operating a 30K scanner at 40K increases the heat inside the scanner dramatically. To prevent that, LARGE-SIGNAL-PERFORMANCE IS SACRIFICED! This means that sure -- teeny-tiny parts of the image can scan faster and will look sharper, but jumps across a screen will actually be made to take longer. THEY HAVE TO, otherwise heat inside the scanner will build up to the point of scanner destruction.

MAKE THEM PROVE IT!

Now, since everyone knows someone on an internet forum who "knows everything", I'm sure there will be some folks here who will say that I am full of BS, or say that he knows a friend with magical technology, or something else and therefore they can go faster (faster than the company that invented the whole galvanometer scanner industry nearly 40 years ago). But anyone who can make such a claim should be prepared to prove it! Anyone wanting to prove it will need to demonstrate to you, and the rest of the world, how they balance these equations:

THE PHYSICS, AND EQUATIONS OF MOTION

Heat inside the scanner = (RMS Current flowing through the scanner ^2 * (Coil resistance * 1.33) * Thermal resistance of the scanner and mount) + Ambient temperature of the mount
RMS Torque produced by the scanner = RMS Current flowing through the scanner * Torque Constant
Maximum Sinusoidal Frequency produceable = SQR(RMS Torque / (Total system inertia * (Angle / 8.22)) ) (where angle is in projected optical degrees)

You won't find anyone else quoting these formulas, let alone showing you how their scanner provides better performance because they have better specifications. In fact, most companies serving the laser light show business don't even give you the specifications of their products (my own belief being because they don't know how to even measure their own specifications in the first place)...

WHAT ABOUT PROJECTED IMAGE QUALITY?

In my opinion, you should not only be concerning yourself with scan speed, but also what's even more important to me is the QUALITY of the scanning. What do your images look like? Are they squiggling and wobbling all over the place, or do they look absolutely beautiful, as if an engineer painted them on the wall? You can see the images produced by Compact 506 for a few folks here on PL here: http://www.youtube.com/watch?v=d7ncsKeTM0Q and here http://www.youtube.com/watch?v=gImSsPJCxw4

BOTTOM LINE

In any event, in my 28 years of working in this business, I've certainly seen a lot of exaggerations over the years of how this company can to this, and that company can do that. But now that we're building our own scanners one thing is obvious. ALL OF THIS IS PHYSICS!!! If someone claims to have a faster scanner, they should be prepared to PROVE it to you, not with more hot-air coming out of their mouth, but with the actual specifications, engineering drawings, and other things that clearly demonstrate HOW their products are supposedly better and WHY their products are supposedly faster. If those who are doing the talking can't demonstrate these things to you, then it could be because they're exaggerating...

In the case of ScannerMAX scanners, we are prepared to demonstrate these things to you. In our datasheets you will notice that our coil resistance is lower than everyone else's (for a given torque). Since heat is proportional to resistance, lower coil resistance means lower heat. Likewise you'll notice our numbers for Thermal Conductivity are better as well. Because of these things, our scanners run cooler. What you WON'T find on literally ANY datasheet is a description of shaft size or how the rotor is made inside the scanner. Our rotors use shafts that are up to 50% larger in diameter, and since stiffness goes as the fourth power of diameter, a 50% larger shaft gives up to FIVE TIMES the stiffness! So our scanners are stronger. Our position signal is also stronger too -- up to 8 times as strong as others on the market, and with anywhere between 1/5 and 1/10 the capacitance, making our signal to noise ratio nigher. All of these factors come into play to make better looking images, and allow the scanners to run cooler.

One thing not discussed in the videos and but briefly touched on by Norty is that we have observed that the large-signal performance of our Compact 506 is actually better than that of Cambridge scanners having similar inertia. What this means is that you can project images wider than you otherwise would be able to project, without distortion. See Norty's comments here.

(Remember, these are our least expensive scanners...)

Best regards,

William Benner

[norty303]

You know what, on pro audio forums that I use/have used, when they want to check out different products, they organise a shootout.
Given that the scanner market is relatively static, it wouldn't need to happen too often.
granted they do throw up all sorts of acusations about whether a particular speaker/amp was a production version or 'special edition' for the test, but I would think some sort of side by side test would be possible at any one of a number of LEMs, using some straightforward tests and user experiences that could be documenteed and re-performed at any number of other meets.

[Pangolin]

but i've found out that doesn't mean you can have 40K at lower angle.

... again, all of this is controlled by physics, so it is 100% predictable.

Your typical 6800-style scanner can produce the ILDA test pattern at 30K, at an angle somewhere between 10 and 14 degrees, depending on the construction quality and other factors.

Since frequency has square-law implications, increasing frequency by 40K / 30K means angle must decrease by a factor equal to 40K / 30K squared. (40/30)^2 = 1.78, so the size of 30K scanners tuned to 40K is reduced to "10-14 degrees" / 1.78 = "5.62 to 7.86 degrees". It means that the absolute best 30K scanners driving small mirrors would not quite be able to hit 8 degrees if tuned to 40K.

Norty sent me DT30 scanners (or maybe 35, I can't remember) tuned to 30K with mirrors a bit larger, and could only produce the pattern at around 5 degrees, even though it was at 30K. See my formula above, which describes how inertia (related to mirror size) impacts performance...

Bill

[buffo]

I would think some sort of side by side test would be possible at any one of a number of LEMs, using some straightforward tests and user experiences that could be documented and re-performed at any number of other meets.

We did this at a Florida Laser Enthusiast's Meeting in March of 2012. We compared the EMS 4000, EMS 7000, DT-40 pro, G-120 , ScanPro-50, Cambridge 6800, and Cambridge 6215 scanners. The results were posted here in the forum. Despite the fact that there were over a dozen witnesses to the event, the results were still questioned, and the drama dragged on for pages and pages of pointless drama spread throughout several threads.

I wouldn't mind doing another shootout at some point. But I'll be damned if I'm going to waste several hours testing something just to prove what I already know, only to have some asshat on the forum question my integrity after the fact. (And no Norty, I'm not talking about you. ) Time is short enough as it is at a LEM... I'd rather be having fun watching shows.

Adam

[norty303]

Norty sent me DT30 scanners (or maybe 35, I can't remember) tuned to 30K with mirrors a bit larger, and could only produce the pattern at around 5 degrees, even though it was at 30K. See my formula above, which describes how inertia (related to mirror size) impacts performance...

For clarity, they are/were DT30 scanners, but fitted with the 'larger than stock' mirrors (God knows I got a long email from Bill about them not being 'large aperture' ) and so DT30's are claimed to be 30k scanners with the normal mirrors, but obviously won't achieve that with the bigger mirrors. I've heard 25-27k quoted in the past, would've been interesting to find out at what speed they hit the magic 8 degrees, but it seems about right in my mind.

to have some asshat on the forum question my integrity after the fact. (And no Norty, I'm not talking about you. )

I could question your integrity if you like, I'm not a proud man...



I think that even with all the 'noise' that results from a shootout, there is good information to be gleaned. I like 'real world' experiences and subjective opinion personally, and to read about them, and to read why people don't agree with results. dsli_jon posted details about why he preferred EM scanner over CT for some graphics jobs in a post a good while back, and it was to do with the more graceful way they crapped out at the limit. thats the sort of thing thats useful. Yes, numbers and scientific tests are good, but only when put into the context of how that affects actual image reproduction and shows. And lots of laserists don't have the knowledge to determine what any given spec means in terms of performance.

[The_Doctor]

In my opinion, you should not only be concerning yourself with scan speed, but also what's even more important to me is the QUALITY of the scanning. What do your images look like? Are they squiggling and wobbling all over the place, or do they look absolutely beautiful, as if an engineer painted them on the wall? You can see the images produced by Compact 506 for a few folks here on PL here: http://www.youtube.com/watch?v=d7ncsKeTM0Q and here http://www.youtube.com/watch?v=gImSsPJCxw4

Is this a rotating line I see before me? Nice one. This pretty much confirms that the 506 will work for me. I attached an image of the 400 Hz WAV file I generated for my original WideMove test. As it shows, I use an interpolator to fill the time between plotted points (which are updated per vertex (point?) , not just once per rotation. In other words, I optimised for smoothness and correctness at every possible instant short of burdening the code (and CPU) with doing it for every SAMPLE, which would have been silly, total overkill... More accurately, linear update IS every sample, but the rotation correction is per-vertex only.).

As I am using what amounts to point spacing even finer than what Bill showed in his second video (with Norty's big mirrors), the rotating line should be much finer, with no bowing (fishing), than it was with the Widemove sticky-hysteresis when starting from rest as the 506 does not seem to have that problem at all (also shown to be the case by the clean sharp scalable text). One reason I chose to use this interpolator was that if I compelled the signal to amount to a series of small steps I was less likely to conflict with large step response I was unable to understand or control as well. The other was that no analog abstract generator is going to make big steps (unless it uses square waves with no bandlimitation whatsoever, an issue that has not yet come up in related discussion, but no doubt will, eventually.)

EDIT:
One thing noticeable is my dwell time at vertices, currently 10 samples at 44100 Hz sample rate. This is as short as Widemoves consistently let me get away with. I'll be interested in whether the 506 will allow me to get away with less. I suspect they will.

[Pangolin]

Is this a rotating line I see before me? Nice one.

Yes, I am pretty sure I made it specifically for you, and the questions you were asking in the thread.

Let me take this time to mention something else that you will, no doubt, understand. This is a corollary to my 30-minute video on ScannerMAX scanners and other scanners. They are *supposed to* work like a low-pass filter. For 30K, the cutoff is 2.5kHz (12 * 2.5kHz = 30K). This was discussed in my video. What was NOT discussed is that this particular behavior is only exhibited in something called "the small signal domain". What it means is -- as long as you are always operating in "the small signal domain", then the scanners will behave like a 2.5kHz low pass filter. Both axis will. So regardless of which line does what -- regardless of the angle, the filter behavior is the same. Both axis will act the same.

Where this stops happening is when you LEAVE "the small signal domain". When does that happen? When the output power amplifier becomes saturated. After that, the servo will basically need to slow down the scanner to prevent overshoot and other ill behavior.

Now -- here is a really important point. If a scanner is really fast -- and has a high torque-constant-to-inertia ratio, you will remain in the small signal domain for a long time -- perhaps for steps upwards of 10 degrees. But if you've got a crappy scanner, you'll exit the small signal domain at smaller angles -- perhaps 2 degrees or even less.

This means that -- while it may be possible to tune two scanners to 30K (one with very good torque-constant-to-inertia ratio and one with a poor one), and while both scanners will behave like a 2.5kHz low pass filter for small signals, the crappy scanner will exit the small signal domain sooner and will exhibit this "fishing" behavior long before the good one will.

But this also illustrates another point and that is SACRIFICE. When you tune a 30K scanner to 40K, what you effectively do is make the small signal domain smaller (easier to exit). So what you SACRIFICE is large-signal performance (this fishing, among other things).

This is all very technical, but what I dislike is when people advertise scanners tuned to 60K, but stop there and say no more. Sure, 60K at how many degrees? How large is the small signal domain? Etc... A lot goes into this. Unfortunately it's not sufficient to say "it goes 60K"...

Bill

PS: I call it "fishing" because in the Laser Media Test Pattern there are lines that are overlapping, and drawn in opposite directions. So when you have one axis acting fast and another acting slow, the two lines will bend in opposite directions -- like a football. For some reason when I saw this I envisioned "fish" rather than "football", so years ago I simply started calling this "fishing". Sort of like how I see dashed lines made by DPSS lasers which look like jelly-beans placed one after another, and I call that "jelly beaning"...

[The_Doctor]

Fascinating (in the eyebrow sense of the word..)... I remember that 1Khz or so was the limit on WideMoves, which clearly relates to the 18-24 kpps spec given depending on angle. 30K will certainly be quite the upgrade.

By saturating the amp, do you mean like clipping? This is a thing I'd avoid if possible, as it presumably relates to the generation of strong HF that is so damaging to tweeters in an audio system if this happens. Even bass units can be threatened by it because they are trying to move faster than their design limit intended.

WideMoves had a very small rotor. This may mean the torque constant ratio is poor. I imagine that as the mirrors will smooth out the extremity of motion that might otherwise arise, this could account for their resilience to overdrive (as stated by Karl (Banthai) some years back), but it is no substitute for strong clean drive and prevention of poor or clipped signals in the first place. This is why I often emphasise good control of more power being better than limiting power to the point where clipping occurs. With a low-powered audio amp it is easy to get destructive power directing large step responses, with an over-powered amp it is usually better for the speakers than an underpowered one driven hard. This relates to torque ratio, and possible other aspects of laser and scan control. Although perhaps a better analogy for low torque constant to inertia ratio might be a speaker with a weak coil and heavy cone rather than a strong coil and light cone. Both will render small sonic detail fairly well, but the attack sound of a bass drum or bass guitar will quickly show up the first speaker as bad.