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Special Projector Features 2

Posted on May 21, 2013 by Art Feierman


"What?" you say? I said Audio. In the past, portable projectors (under 10 pounds) mostly have been skimpy in terms of sound. You'll notice today, that almost all of the projectors in this report are under 10 pounds - thus technically portables. Still many of today's portables really are designed as portable/or/fixed projectors.

Usually a couple of 0.5 watt, or 1 watt, or maybe a 2 watt speaker, is all you find in most projectors. That gives the average portable projector a bit more sound than a typical laptop, but less than the typical pair of small, cheap speakers that come with most desktop computers.

One or two of those tiny speakers isn't going to carry in a classroom over two or three dozen students. It's just not going to cut it.

And, for that reason, over the last 7-8 years we've been seeing more and more projectors with healthy sound generating abilities, as the manufacturers have come to realize that schools are the largest viable market for projectors. Now, at least for those projectors targeting the K-12 and university classrooms, at least a single 5 watt system. Other common "louder" projectors have a single 7 or 10 watt speaker, one projector I've encountered even has 4 five watt speakers but that one's not in the report.

In days gone by, AV and IT co-ordinators knew the tiny speakers in most projectors wouldn't do the job, so they would also have installed at least one more powerful speaker, and run power to it from (most likely) the same computer and video player that feed the projector. Some projectors have an audio output, which would work fine to feed that extra (powered) speaker system. That's simpler than running additional wires from the equipment, but life is still simpler, and lower cost, if the projector has enough sound that it doesn't need any help.

For that reason, when we're considering projectors for education, expect to find that most all the projectors we've reviewed have 5 watts or more of sound, and should be fine in a typical classroom, assuming the teacher has any control at all, over his/her students. One more thing. Please don't expect any serious bass out of these projectors. They weren't designed for the 1812 Overture. This year, however we do have a few projectors with "small sound."  That includes our one Pocket projector, and a couple of the most lightweight/portable of the rest.

Edge Blending and Color Blending

These are features typically found on more expensive projectors than those found in most classrooms, but using such features is more likely to occur at the university level in large classrooms and other areas.

There may be times when the traditional widescreen projector just doesn't project a near wide enough image for a special application.

If you have two or more projectors with edge blending, they can seemlessly display that much wider (or taller) image, so that you cannot detect where one projector's image stops and the next one begins.  Once a technology that relied mostly on expensive outboard processors, and cameras for alignment, edge blending is showing up in more and more larger fixed install projectors, including some costing less than $5000.

Color Blending, as you would expect, is built on the same content.  Let's say we're showing an 8 foot high, 30 foot wide image of an architectural rendering of a bridge.  It's great that you can seemlessly see the entire bridge, but it would be sort of dissappointing of you could easily spot color shifts where one projector ends and the next begins.  And color shifting is exactly what you could expect.

With color blending, the color is analyzed and adjusted so that in conjunction with edge blending, a viewer likely couldn't even spot where one projector stops and the next one starts up.  These features are appearing in museums, art galleries, art and architecture projects and likely in some scientific and engineering areas as well.   With the cost of edge and color blending becoming relatively small, when a project already calls for a high power, high image quality projector, expect the use of edge blending to continue to come down to even less expensive projectors.

Active 3D Projectors

The vast majority of commercial projectors (including education projectors some of which sell for less than $500, that offer 3D.  Activ 3D also includes some incredibly expensive home theater projectors with 3D.  Active systems use LCD shutter glasses.  The way it works is that projector feeds 3D data alternately to one eye, and then the other.  To make this work, a system is needed so that the left eye doesn't "see" the image that was intended for the right eye.  To accomplish this, active 3D glasses sync to the image.  The glasses left lens is virtually clear when it is time for that eye to see the "left" image".  Then, the shutter makes the left lens opaque when it's time for the right eye to see the "right" image.  At that point the right lens is clear. This all happens very quickly typically with the projector shooting 120 frames per second - 60 for each eye.

There are basically two drawbacks to active 3D setups. First, some folks find active 3D harder to view than passive systems (passive is what you'll find in most 3D movie theaters - at least in the US, with low cost non-active, polarized glasses. The other drawback, which is a potential "killer" in the classroom, is the cost of the glasses.  Most manufacturers price their active glasses around $100 a pair, perhaps +/- $30.

The good news is that 3rd party 3D glasses tend to sell for a lot less.  A quick scan of the internet shows the least expensive, brand X glasses at under $30, while there is a good selection of "universal" glasses in the $40 - $60 range.  (Universal doesn't mean they work with all projectors, it means they work with a group of projectors that are compatible with "universal projectors".  A good example are DLP-Link glasses. Most DLP projectors with 3D use these.  They get their syncing signal transmitted with the image.  Other systems use RF, even Bluetooth, I believe.

The cost however, deserves more attention here. As pointed out many times in this report, the high cost of glasses, is murder on school budgets.

Even if a school needs 35 pair for one classroom, and they are a very affordable (for active glasses) $40, that's $1400 for glasses, perhaps going with a $500 or $800 projector.  Ouch.   Worse, we're talking schools here.  Does anyone really believe that a number of pair of these glasses will NOT dissappear or be broken over time?   If a school is thinking the projector will last just 5 years, they probably are also thinking they just might need 50 or even 100 pair to get through those 5 years, even if class size never exceeds 35 students.  That makes glasses costs in the $2000 to $4000 range.

For this reason, there has been interest in a 3D solution that uses passive 3D instead, because glasses cost only a few dollars each, solving the long term loss problem.

Passive 3D Projectors

Of the 10 projectors in this year's education report that are 3D capable, only one offers Passive 3D.  And we were sufficiently impressed that it won this year's Best In Classroom - 3D Projector award, whooping all 9 of the active systems.  Let's consider first, though, how they work.

Ultimately, the distinct advantage in the classroom, or the movie theater, is the low cost of glasses compared to active glasses, but before we cover that:

With Passive 3D, a polarizer is normally used, instead of shutters.  This can be accomplished by using a polarizing device.  We reviewed the Lightspeed DepthQ system a couple of years ago, that can be used with many projectors for passive 3D (expensive devices, the Depth-Q started around $5000, just add a compatible projector - which could be almost any 3D active capable projector). A single polarizing device requires that you are still alternating from one eye to the other, using an interlacing type of method, half of the vertical resolution is polarized one way, the alternate lines, the other. But there's another way.  That is using a two projector method.  That's also the way Runco does extreme high end 3D, with a projector with two lenses!

But let's stick to commercial applications, such as the classroom.

To make passive 3D work with two projectors, each projector will need to have a polarizing filter in front of its lens.  One filter will polarize the image in a circular fashion in one direction, while the filter on the other projector polarizes it in the opposite direction.  Since both projectors can present their image to the respective eye (left or right) at the same time, both eyes are "working" all the time, not on off, and that tends to be "easier on the eyes" or rather, easier on the brain.  Consider that fact alone to be a plus.

But it also means that with two projectors you've got more brightness as well.  And since an active system usually, effectively gives up about 75% of brightness (compared to 2D brightness) that's a very important consideration. Passive setups inherently do get more lumens to your eyes, consider that passive systems can approach 50% of the brightness of 2D. If you have two projectors working, each about the same brightness as one projector doing active, then expect to get a drastically brighter image. Figure the number could approach being 4 times as bright, but we'll settle for an arbitrary 3 times as bright for the sake of this conversation.

From a practical standpoint in this year's educational report, the one passive system produces 3D with a brightness approaching most equivalent 2D projectors.  Of course that system has two 3000 lumen projectors, whereas most competing projectors are 2500 to 3500 lumens.

The trick to successful dual projector setup is to have the projectors perfectly aligned with each other. Ideally lens shift is the way to stack projectors, but, lens shift is an uncommon feature in lower cost projectors.  Keystone or corner correction, by comparison are digital solutions that cause cause some softening of the image.  Lens shift does it optically with net superior result.  None-the-less, Epson proves it is viable to do, with their W16SK projector.  I would expect to start seeing more stacked projectors for 3D use, if the Epson system catches on.

Cloud Projectors / Cloud Presenting

Cloud computing is more of a new spin on an existing capability.  Essentially, a Cloud projector is capable of running presentations off of a remote server (or a local one).  A cloud projector, can of course be standard, short or ultra short throw, it can have all the usual tributes found on projectors, it can be a fully interactive projector.

A recently reviewed projector with cloud capabilities, the Mitsubishi WD390U-EST (an ultra short throw projector), could do all of these things:

  • plug in a keyboard and mouse into a projector, and then use them to navigate around a connected server, running various documents including pdfs, docx, txt, jpg, and ppt files
  • Project from a remote computer, connected via network
  • Be able to take run that computer and it's presentation using an iOS or Android device, such as an iPad
  • Run PC free presentations and files from one of its USB ports

Consider a cloud projector to be one with good networking skills.

PC Free Presenting

Some projectors have built in "Players" so that you don't need to bring along a computer, only the computer files you want to show.  These players are essentially a small computer designed to display files such as txt, gif (geek trivia:  gif is pronounced with a soft "g" like the peanut butter - according to the inventor of the file format, and contrary to how most pronounce it), pdf, doc/docx, jpg, gif, and ppt.  Different players may support different file types.  Some support video others do not.

Essentially a user places files they wish to present onto a USB thumb drive, and place it in the appropriate USB port.  Typically on projectors so equipped, select the USB source, and the player will normally start up, and show you a directory of what's on the USB drive.  Often it will start off by giving you a menu to choose what type of files you are looking for, such as:  Video, Images, Documents, PDFs.  And then it will show you the files of the type that you selected.  Generally such players are straight forward to use with old style file directory systems, but often could be more user friendly.

There are limits to what is done on different, PC Free capable projectors, in terms of viewing capability.  Some projectors might have an impressive set of transitions, even the Ken Burns effect built in for viewing images, multiple timers, and many other special effects.  Others are pretty bare bone.   (Ken Burns zooms in or out slowly and slightly shifts each picture.  It is widely used on websites, and in presentations of all types where images in etc.)   The same might be true of document readers, with some having zoom capabilities, and even basic annotating, others may be very simple.

Interactive Projectors

In this day, and age, a signifiant, perhaps the majority of projectors have at least one interactive feature.  If you have the ability, for example to go from one powerpoint slide to the next from the projector's remote control, that's interactivity.  Remote mousing is also interactive - having the projector's remote doing what a mouse can do, but remotely.

That said, when we're talking about Interactive projectors we're going well beyond basic mouse functions, and we do not include these simpler interactive features as qualifying a projector to be called Interactive.

Most typically, today's serious interactive projectors have a pen or alternative device.  With it you can write on walls (no ink), white boards, even projector screens (be careful).  You not only have all those basic remote mousing functions, but lots more, such as using the pen to type on a projected keyboard.  You can highlight and edit, and drag. In conjunction with a computer being used, in some cases you can even record the entire session, including what is projected from a source, as well as what you have added with the pen.  It should be noted, that there are now a number of companies who's pens don't even have to be near the screen to work.  With many you can stand 5 or 20 feet from the screen and underline, and highlight, etc.  (The further away, the coarser your accuracy will be.)

A growing alternative, or in addition to the pen, is using a mobile device.  We've reviewed several projectors with the ability to perform significant interactive functions using an iPhone, iPad or Android device.

Still other projectors will present directly from your mobile devices.  How about using an iPhone to control an iPad that can present on a projector.  Technically one could argue that the projector is almost incidental to that type of interactivity, (it's more the software app provided by the projector manufacturer and likely it will allow full control of the projector's functions as well.

Interactive projectors are consider to be of major benefit in teaching situations.  Both for use by the instructor, to educate and captivate.  (use that pen to slide in another page, or toss one away - quickly).  These projectors may not be up to the interactive technology in the latest James Bond movies, but they aren't completely without serious skills, given well designed content, and great onboard tools.

If there's a flaw as far as interactive projectors go, in terms of use in schools, it's their relatively high price tag.  I'd say the typical interactive projector is probably about 50% to well over double a more basic projector.  Why is that?  First, most competent interactive projectors would be very short throw or ultra short throw, so that the user can avoid being constantly blinded by the projector and casting a large shadow. There is definitely a premium price for ultra short throw projectors.  We've looked at several $1000 plus ones in the last couple of years and some of the best arre around or more than $1500.   Compare the cost to a more traditional projector which might be $400 - $800 depending on feature sets.

The higher prices create a tough choice for a school planners - do we equip 25 classrooms with more basic projectors, or only equip 10 or 15 with interactive projectors?

BYOD - Bring Your Own Device.

Thanks to a number of projector apps out there currently, presenting is no longer limited to content on computers and video players.  Android and iOS devices are now able to work with a large number of projectors, with more and more projector manufacturers producing such apps.

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