Plasma TVs at Altitude
Reviewer: Phil Conner
NEC is left as the only provider of "high-altitude" plasma TVs and displays though Pioneer now states 7500 feet and Panasonic states 7800 feet for their plasma TVs. NEC has implemented their altitude freindly technology in all of their current plasma displays which are rated to 9180 feet. From my experience with these, they have worked perfectly at altitude with no side effects and no noise complaints.
Altitude has long been a factor affecting the performance of plasma TV. The display elements of plasma units actually consist of rare natural gases (like xenon, neon, and argon), which have been compressed inside hundred of thousands of tiny glass envelopes. Ideally, the pressure these gases are under should match the pressure of the gases (N2 and O2, mostly) outside the walls of those glass envelopes. At sea level or thereabout, these two pressures are more or less equivalent, for this is the atmospheric pressure level at which most plasma televisions have been calibrated. The thinner air at higher elevations causes an air-pressure differential-an imbalance between inner and outer air pressures-and the pressure of the gases inside the plasma display panel (PDP) increases as the outside air pressure decreases. Hence, most Plasma TVs (at least those not specifically designed for use at or above 5500 feet) emit a slight buzzing noise under such conditions. This noise is the result of the PDP's increased power consumption and the corresponding increase in its cooling needs and, hence, its fan usage.
What are the symptoms of "altitude sickness" in plasma display panels operating at or above 6000 feet?
There is very little difference in visible picture quality. The chief high altitude symptom you'll detect will involve your plasma televisions' operational noise levels. Because of the increased pressure on the gases contained in its glass substrate, the unit must work harder to cool this display element. So, if your plasma TV set has fans, the fans will be significantly louder because they're running harder. If your Plasma TV utilizes a convection cooling system (one without fans), then you'll notice something akin to a buzzing sound emanating from its rear panel. Another thing to consider with respect to altitude and plasma TV is longevity: Since PDPs work harder at higher elevations, they will not last as long up high as they do down low.
So, what does all this mean for someone living in Denver, CO, for example?
At 5295 feet, Denver lies well under our new recommended limit of around 6500 feet. Pioneer states maximum altitude of 7500 feet. Panasonic now states maximum altitude at 7800 feet. NEC's plasma TVs are rated to a maximum of 9180 feet. With Sony's exit from the plasma TV market, NEC is left as the only provider of "high-altitude" plasma TVs and displays. They have implemented their altitude friendly technology in all of their current models. From my experience with these, they have worked perfectly at altitude with no side effects and no noise complaints.
Also, you might also note the fact that atmospheric pressure seems to differ geographically. We have anecdotal evidence of this bizarre-but-true claim in the form of telephone conversions we have had with plasma TV owners nationwide. The same TVs seem to be affected differently by different altitudes. So, for example, one person reported a considerable noise coming from his TV at 5500 feet, while another person with the same model TV reported hers working just fine at 6500 feet. Air pressure is influenced by variables other than just altitude
If you live above 6500 feet, you might want to visit a local AV store to determine whether or not they have had any problems - and which models are performing best.
LCD and DLP display technogolies do not contain high altitude quirks, so keep them in mind if you need alternatives to plasma.
Not sure what your hometown elevation is? Click here to get the figures: http://www.calle.com/world/US/