RE: Slightly OT: home cinema

["Keith Doxey" <ukha.diyha@xxxxxxx>]

Hi Tim,

 

As I have said before ......its "Horses for Courses" 

 

There are several ways to view a picture and each has benefits and drawbacks.

 

Direct View CRT.

+ Cheapest method

+ Established and well refined Technology.

+ Handles multiple resolutions without noticeable artefacts on picture

- Bulky

- Prolonged display of a Static image can burn the face of the tubes

 

CRT Projection

+ well specified projectors at reasonable prices

+ superb image quality when correctly aligned

+ established and well refined technology

+ runs cool so very little fan noise from projector

+ Long Tube Life generally well in excess of 10,000 hours

+ effectively uses 3 monochrome tubes with no shadowmask so has almost infinite resolution

- Light output can be fairly low

- Best in darkened rooms

- Prolonged display of a Static image can burn the face of the tubes

 

Plasma Direct View

+ Looks really cool

+ Very thin display

+ Bright

- Fixed resolution *

- New technology still developing - longevity of displayed image quality unknown.

- Suffers BADLY from screen burn when static images are shown

- VERY Expensive

 

LCD Direct View

+ Compact

+ Looks cool

+ Bright

- Fixed Resolution*

- Image degrades badly when viewed off access (although newer displays are better)

- DEAD PIXELS*

 

LCD/DLP Projection

+ Compact

+ No convergance required, just zoom and focus

+ Bright

- Fixed Resolution *

- Runs VERY hot requiring noisy fans to keep cool

- Short Lamplife

 

* FIXED RESOLUTION

the display element of Plasma/LCD/DLP has a finite structure of X by Y pixels. An image displayed at the NATIVE resolution will look superb. However, an image of a different resolution can only be displayed by adopting one of two compromises. Using the example of an SVGA 800x600 LCD.

 

1. Blanking - Displaying the incoming signal at its resolution and showing black on the rest of the screen

    A 640x480 VGA signal would have black bars all round but show a perfect VGA picture in the centre.

 

2. Scaling - Compressing or Expanding the picture to fill all available pixels. scaling technology is constantly improving but artifacts are still noticable particularly on computer text where lines appear to be missing(compression) or thickened (expansion).

 

A conventional CRT has a shadowmask which effectively give it a fixed resolution but as the size of the dots is much smaller than the displayed size of a pixel any artifacts an negligable. A CRT projector uses three guns without shadowmask so effectivly has infinate resolution.

 

Imaging trying to draw something on A4 paper.

A CRT is like plain paper - you can draw anything anywhere

Plasma/LCD/DLP - is like 1mm graph paper - you canonly draw by colouring in complete squares (pixels).

 

I agree entirely with your point about not having to draw the curtains or dim the lights, but I dont think I have ever been to a Cinema that had windows, and when they leave the lights on as people enter, you cant see the screen too well. They turn the lights out when the main feature starts.

 

What you have there is a very impressive but expensive telly.

 

In my mind, the whole concept of Home Cinema is to recreate a real cinema on a smaller scale. Therefore when I sit down to a movie its phones off, lights out, popcorn and drink to hand, Action.

 

The only thing I have seen BETTER than CRT fot Home Cinema is LIGHT VALVE.

this is a hybrid of all technologies.

 

An Infra red CRT for each of the RGB signals (effectively infinate resolution) shines on an LCD mirror which changes its reflective properties. A Xenon Arc lamp is split into Red Green Blue and sent to 3 of the above assemblies. It is then recombined by prisms and mirrors and fired at the screen. It can not suffer from Screen Burn.  I saw one demonstrated at PLASA a couple of years ago. 44ft x 24ft picture 100Hz, Extremely bright, Superb contrast, better than 35mm film. They also showed computer generated images as used in a simulator ride. It was a roller coaster film that I has seen in a simulator ride and I felt as if I was moving because of he sheer size and quality of the image. These are the projectors that are being trialled for digital Cinema by companies like Virgin.

 

In the last paragraph you got all the PLUS points of Light valve. Now the NEGATIVE point of Light Valve..... £250,000 EACH. Makes Plasma look really cheap !!

 

enjoy your Plasma but watch for the image fading, it has happened to all the Plasma Panels we have at work and the oldest are only about 15 months old :-(

 

Keith

 

 ----- Original Message -----

From: Timothy Morris

 

To: ukha_d@xxxxxxx

Sent: Saturday, April 07, 2001 1:16 PM

Subject: [ukha_d] Slightly OT: home cinema

 

As many of you are no doubt aware Home Cinema really is a love of mine (my interest in Home Automation really is just limited to infra red lights and curtain control).

 

I've just laid out an obscene amount of cash on a Panasonic 42" plasma display screen and an Arcam DV-88 DVD player.

 

I played Gladiator on it last night, and it is the best quality picture I have seen outside a West End cinema. OK, the SIZE of the picture cannot compete with a CRT projector, but the quality is awesome. This together with the flexibility of Plasma (you don't have to shut the curtains and turn off the lights) warrants a wholehearted recommendation.

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