TV Specs and Settings – Are they for real?
There is a great article at Maximim PC by Dr. Raymond Soneira called “Display Myths Shattered: How Monitor & HDTV Companies Cook Their Specs.” We’re going to distill it down to a few soundbites and add a little bit of HT Guys color commentary along the way. But if you find the information interesting or useful, we would encourage you to read the full article.
Background on TV display settings
Most of you probably already knew that the four main display settings on your HDTV: brightness, contrast, tint, and sharpness, originated with the analog NTSC color TVs of yesteryear, dating back to the 1950′s. Most of those settings had specific meanings back then, and for the most part, they don’t apply anymore.
Back then Brightness was really an adjustment of the bias of the unit. Bias is an adjustment of how many electrons are hitting the phosphors of the screen. It’s a negative offset, so zero bias is full brightness and adjusting the bias will eventually result in no phosphors hitting the screen or total blackness. Contrast controlled a gain factor applied to the color signals shot at the screen, adjusting the overall luminance of the picture. So, in essence, contrast was a brightness adjustment as well.
The other two are very technical, so in Dr. Soneira’s words (because we couldn’t find better ones of our own): “tint controlled the phase of the color subcarrier, and sharpness performed analog high-frequency peaking to compensate for the limited video bandwidth of the old vacuum tube amplifiers.“ But ultimately, the bottom line is that none of these controls are necessary for or relevant to the digital signals and televisions we use today.
Settings to Avoid
Almost all of the settings you see listed as “special” technologies on the brochure or the side of the TV box should be turned off immediately. In most cases, it’s difficult to determine what those settings actually do. And in many cases they actually decrease picture quality. These settings come by dozens of different names and acronyms, many of which are listed in the article. A few that stood out to us were: Dynamic Contrast, Black Level, Gamma, White Balance, Digital NR, DNIe, Detail Enhancer, Edge Enhancer, and Film Mode.
Contrast ratio, or the ratio of brightness between full white and full black on screen can be a very revealing number. Since most sets can go full white, it really tells you how black a set can get. Keep in mind that really good contrast ratios only matter if you’re watching very dark content, like you see in some movies. Most TV viewing never gets into the full black range. Contrast ratio can also be canceled out by the ambient light in the room. No matter how dark the picture gets, it can always be washed out if you can’t control the light that doesn’t come from the screen.
Possibly the worst misuse of a spec is the so-called dynamic contrast ratio. We have talked about this on the show before. It is a measurement of the ratio of white when the full screen is white to black when the full screen is black. Many televisions can actually reduce or turn off the light source entirely if the screen goes full black, producing an incredibly high ratio. The problem, however, is that the sets cannot do this if they’re actually displaying a picture, so you never see anything that dark and the spec is completely useless. What’s worse is that many manufacturers are leaving the word “dynamic” off the spec sheet, claiming contrast ratios in the millions. That just isn’t accurate.
This was a huge eye opener when we first read about it a while ago. It turns out that LCD response times, a spec we always thought was very important, is somewhat meaningless these days. First of all, it would take about a 16ms refresh rate to support 60 fps video. Most, if not all, LCD TVs on the market today are significantly below that threshold. Secondly, in Dr. Soneira’s test, the actual measured response time was significantly higher than the published spec. An 8ms SONY LCD had a measured response time of about 65ms, and it was the best performer in the group.
Another equally useless spec that is somewhat related is refresh rate. In an independent test, many viewers were able to see improvements (reduction in) blur on 120Hz televisions over 60Hz sets if they were shown a still image moving quickly across the screen. The same people saw no different when watching actual video content. Since what we watch on TV is very rarely a still image moving quickly across the screen, it stands to reason that there is little if any benefit for normal use, of a 120Hz TV over a 60Hz model. Of course the 120Hz sets tend to be newer, with newer electronics, so it’s entirely possible that they have better picture quality – but not due to the refresh rate alone.
The article goes on to discuss color gamut and how manufacturers reaching to give you a “wider” color gamut are just playing specmanship with you. This also applies to Sharp and their new quattron or quad pixel technology. According to the article, you won’t get any benefit from that extra yellow in the color array. The content you’re watching is balanced for the RGB sets most people own, which already include yellow.
The article was very informative and gave us some really good food for thought. Our main takeaway was that your eyes are all that matters when it comes to TV picture quality. Regardless of what specs are published, what you see on screen is what counts. Find a TV that works for you, and buy it. So what if someone else has a higher dynamic contrast ratio, faster response time or a wider color gamut. Odds are, nobody can tell the difference anyways.
Posted by The HT Guys, June 10, 2010 11:24 PM
About The HT GuysThe HT Guys, Ara Derderian and Braden Russell, are Engineers who formerly worked for the Advanced Digital Systems Group (ADSG) of Sony Pictures Entertainment. ADSG was the R&D unit of the sound department producing products for movie theaters and movie studios.
Two of the products they worked on include the DCP-1000 and DADR-5000. The DCP is a digital cinema processor used in movie theaters around the world. The DADR-5000 is a disk-based audio dubber used on Hollywood sound stages.
ADSG was awarded a Technical Academy Award by the Academy of Motion Picture Arts and Sciences in 2000 for the development of the DADR-5000. Ara holds three patents for his development work in Digital Cinema and Digital Audio Recording.
Every week they put together a podcast about High Definition TV and Home Theater. Each episode brings news from the A/V world, helpful product reviews and insights and help in demystifying and simplifying HDTV and home theater.