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StevenSurprenant
04-06-2009, 05:08 AM
There are two things that I want to mention ...

I've read that putting a light behind your TV creates a seemingly better picture in a dark room. I've tried this before with less than stellar results, but last night I apparently positioned the light in the correct position and everything fell into place with great results. The articulating bracket that I use for my wall mount TV makes the TV sit out from the wall about 3 or 4 inches. At first it looks odd, but I think that it's because we aren't used to it. Once I got past that preconceived notion , it makes the TV appear to float in mid air which is actually really cool looking. It also gives me room to place the light behind the TV. I placed an under counter florescent light on top of the wall mount and against the wall. Of course, this is behind the TV. That position lit up the wall behind and above the TV without creating any bright spots. It also lights up the sides of the TV a bit to accent that floating appearance. The end result was a better picture. I think the key here was the lack of bright spots from previous light positions that were distracting.

I have a Samsung LCD TV and as most of you know, LCD TV's don't have the black level that plasma's do. I noticed that TV watching in the day time was great with apparent black levels that rival most plasmas and surpass some plasmas. I realized that this effect is caused by the iris of the eye being slightly more constricted because of the ambient light in the room. When the room is totally dark, it is easy to see the “lack” of total blackness of the LCD although the picture is still very good. By placing the light behind the TV, it causes the iris to slightly close which in turn causes the black to “appear” darker, hence the picture becomes more 3D. Any way, the light stays!

The second thing is that many of us sit so far back from the TV so that we cannot tell the difference between 720 and 1080. I noticed that when I would get closer to the screen I would see more detail. It occurred to me that by sitting too far back, we aren't getting what we paid for. I moved my chair much closer and the results were spectacular. I went from sitting 12 foot to sitting 7 foot from a 52 inch screen. The picture quality determines the best distance to watch from.

Between the light behind the TV and sitting closer, the results were awesome. The chair sitting in the middle of the room looks odd, but who cares. Just move the chair and get rid of the wife, if that's a problem. Just joking!

There was one more benefit...

By moving the chair, I was further away from the rear speakers which created a more even sound field and therein a better listening experience. It also caused the room to seem bigger that it actually was.

All pluses!

The suppose that the same thing could be accomplished with a bigger screen and a bigger room, but that is something that many of us cannot afford.

The reason I brought this up is because I was hoping that others could benefit from this experience.

Any thoughts?

BadAssJazz
04-06-2009, 12:21 PM
The light behind the TV...wasn't that what Phillips was shooting for with some of it's early Plasma and LCD models?

pixelthis
04-06-2009, 01:27 PM
The light behind the TV...wasn't that what Phillips was shooting for with some of it's early Plasma and LCD models?

Yeah, but you can do it with a light connected to a dimmer and switch.
I havew always watched TV this way, it helps reduce eyestrain and increases
overall PQ.
wont get as good as this of course:1:

StevenSurprenant
04-06-2009, 02:02 PM
From this web site...

http://www.cinemaquestinc.com/ideal_lume.htm

All TVs require a darkened room to present their best picture. The color, point of origin, and intensity of light in a viewing environment, all affect the quality of image obtainable from any television, as well as the viewing fatigue experienced. A small fluorescent fixture, with a proper 'color temperature' bulb, placed behind a direct-view monitor, flat panel TV, or rear-projection set, fulfills much of what is needed to achieve the SMPTE recommendations pertaining to ambient light in the room. Viewing a TV in a darkened room can cause eye strain in short order. This is primarily due to the iris opening and closing dramatically as scenes change from dark to light on the screen. For a vivid demonstration of how frequently light levels change throughout a typical program, turn your back to a TV in a darkened room and notice how much the light changes in the room, both in intensity and frequency. Providing a small amount of light behind the set 'biases' the iris (reducing the range of motion in the iris muscle), resulting in more relaxed viewing. Glare and reflections are then dramatically reduced, by eliminating any light source from striking the front of the set. Colors appear richer and blacks are darker. Contrast and brightness controls can be turned down. Doing this will prevent over-saturation of phosphors, thereby reducing the risk of 'screen burn-in and preserving maximum sharpness and detail. This also preserves correct picture geometry and actually prolongs the life of picture tubes. Phospor life will also be extended for plasma panels and LCD monitors with adjustable cold-cathode fluorescent backlighting.

Kevio
04-06-2009, 06:18 PM
I have 40w lamp on a table beside the TV. Before, I didn't know why that was comfortable. Now I do - biases the iris, does not create glare. Thanks!

Smokey
04-07-2009, 06:16 PM
Yeah, but you can do it with a light connected to a dimmer and switch.I have always watched TV this way, it helps reduce eyestrain and increases overall PQ.


You might have two problems with this setup. I don't think you can use a dimmer with a fluorescent tube lamp (regular light bulb will not do), and dimmer switches create alot of noise which might creep into your HT system.

pixelthis
04-07-2009, 11:00 PM
You might have two problems with this setup. I don't think you can use a dimmer with a fluorescent tube lamp (regular light bulb will not do), and dimmer switches create alot of noise which might creep into your HT system.


TRUE nuff dat.
But I have a simple light control system from Radio shack, with modules that the light plugs into, control signals are sent through power lines, no interferrence if you are carefull.
And while it works fine with flourescent, I find that a small 40 watt incandesent bulb works fine when its dimmed a bit, in fact the slightly "warmer" light sometimes helps the pic.
And I can turn on the coffee pot from my bed when I wake in the morning.
Cheap but it works.:1:

Woochifer
04-10-2009, 04:35 PM
The light behind the TV...wasn't that what Phillips was shooting for with some of it's early Plasma and LCD models?

I believe that they still tout the Ambilight feature on their overseas market TVs (the Philips TV brand in the U.S. is nothing more than a rebadge for Funai). As others have said, the utility of using a backlight with a TV is real. There are standard recommendations on the color temperature that you should use on a projected backlight. And I have seen some home theater sites that sell floor-mounted hood lights that project the light up a wall.

StevenSurprenant
04-11-2009, 08:32 AM
You might have two problems with this setup. I don't think you can use a dimmer with a fluorescent tube lamp (regular light bulb will not do), and dimmer switches create alot of noise which might creep into your HT system.

Guess what...

There are dimmable fluorescent lights!

Google it and you will see.

This is new to me too.

http://www.neptunlight.com/images/LINEUP-dim.JPG

Smokey
04-11-2009, 10:00 PM
Thanks Steve. But they seem to be rather pricey since they specifily have to be labeled as such.

Kevio
04-12-2009, 06:00 AM
Yes expensive and the dimming range is fairly narrow - dim them below about 40% and they just go dark.

StevenSurprenant
04-12-2009, 06:39 AM
Until the price of dimmable bulbs drop, you can buy 3-way florescent bulbs at you local hardware store today and they are not that expensive. I just saw them at Menards.

Since we buy these because of their low power consumption we should consider their efficiency and life span.

Lifespan.......................................... .....................

http://en.wikipedia.org/wiki/Compact_fluorescent_lamp

Incandescent lamps are usually manufactured to have a lifespan of 750 hours or 1,000 hours.

CFLs typically have a rated lifespan of between 6,000 and 15,000 hours.

Now consider WOLED devices that are currently in development...

http://www.universaldisplay.com/default.asp?contentID=615

Our team recently announced an all-PHOLED device structure with an operating lifetime of 200,000 hours

Efficiency........................................ .......................

The luminous efficacy of CFL sources is typically 60 to 72 lumens per watt, versus 8 to 17 lm/W for incandescent lamps.[19]

http://www.universaldisplay.com/default.asp?contentID=616

Most recently, we reported a record power efficiency of 102 lm/W. These achievements represented important steps toward DOE’s long-term SSL research goal of a 150 lm/W device in a cost-effective, market-ready white lighting OLED product.

Another company called Cree has this offering...

http://en.wikipedia.org/wiki/Light-emitting_diode

In 2006 they demonstrated a prototype with a record white LED luminous efficiency of 131 lm/W

As of this time the life expectancy of LED lights are about forth that of PHOLED...

http://www.creelighting.com/longevity.htm

The longevity of the Cree light is unmatched. Install one LR6 and expect 50,000 hours of light, and eliminate outages and the need to replace and dispose of lamps.

A Generation of Light
What is 50,000 hours? It is 50 times the life of a typical incandescent bulb and 5 times the lifetime of an average compact fluorescent lamp. In fact, if you ran one Cree lamp for 6 hours per day every day, it would last for nearly 23 years. That is five presidential elections, a home remodeling or a full generation.


Something to think about!

It also occurs to me that if we were to use PHOLED light, these lights could last for, not just a generation, but a full lifetime. Imagine that!

One last thing that I discovered...

The lifetime of any lamp depends on many factors including operating voltage, manufacturing defects, exposure to voltage spikes, mechanical shock, frequency of cycling on and off, lamp orientation and ambient operating temperature, among other factors. The life of a CFL is significantly shorter if it is only turned on for a few minutes at a time: In the case of a 5-minute on/off cycle the lifespan of a CFL can be up to 85% shorter, reducing its lifespan to the level of an incandescent lamp.[10][11][12] The US Energy Star program says to leave them on at least 15 minutes at a time to mitigate this problem.

CFLs produce less light later in their life than they do at the start. The light output depreciation is exponential, with the fastest losses being soon after the lamp was first used. By the end of their lives, CFLs can be expected to produce 70-80% of their original light output. [13] The response of the human eye to light is logarithmic: Each f-number (or photographic 'f-stop') reduction represents a halving in actual light, but is subjectively quite a small change.[14] A 20-30% reduction over many thousands of hours represents a change of about half an f-stop, which is barely noticeable in everyday life.