Panasonic's 2012 plasmas are beginning to hit store shelves. The line includes six series: (from top to bottom) the VT, GT, ST, UT, U, and XT Series. In the middle of the pack is the ST Series, which includes screen sizes of 50, 55, 60, and 65 inches. The ST Series lacks the THX certification found in the higher-end GT and VT models, and a few technological differences exist that I will highlight throughout this review. What you do get with the ST Series is the latest Infinite Black Pro panel with the new Louver filter, 2500 Focused Field Drive technology to improve motion resolution, built-in WiFi, VIERA CONNECT, DLNA media streaming, and 3D Real Sound with the new 8-Train speaker panel. The 55-inch TC-P55ST50 carries an MSRP of $1,699.99.

Additional Resources
• Read more plasma HDTV reviews written by Home Theater Review's staff.
• Explore Blu-ray player options to pair with the TC-P55ST50.
• Find a soundbar in our Soundbar Review section.

Setup & Features
After years of offering TVs with a lackluster (Panasonic prefers the word "conservative") aesthetic, the company has stepped it up in the design department lately to better compete with some of those super-stylish LED-based LCDs. The ST50 lacks the one-sheet, bezel-free design of the top-shelf VT50, but its appearance is still a big improvement over past models. Panasonic has reduced the bezel size to about an inch all the way around the screen, the frame is glossy black with a clear acrylic border, and the square base has a brushed metal finish (oddly enough, the base for this year's 55-inch model does not swivel). The TV measures 1.8 inches at it deepest part and weighs about 62 pounds without the stand. One of the ways Panasonic has reduced overall depth is by redesigning the TV's speakers: The new 8-Train system features eight dome-type micro-speakers that measure only about eight millimeters thick and run along the bottom of the front panel (four on each side - each speaker looks a bit like an SD card slot), plus a 22-millimeter-thick subwoofer that's mounted to the rear panel. New "sound lifting" technology is designed to more effectively redirect the sound to the center of the screen.

The remote control's general appearance is the same as last year's model, but Panasonic has rearranged some of the buttons in a manner that I find more intuitive. All of the function buttons are closer together near the top of the remote, the amber backlighting isn't quite so bright, and the remote now has a glossy black finish that better compliments the TV. As I write this, the VIERA Remote app for iPhone/iPad is still version 1.10 (released in August 2011), but Panasonic has said that v2.0 is coming soon; the upgrade will reportedly offer improved touchpad (slider) operation, a game-pad layout for VIERA CONNECT games, and the ability to flick content (Web pages, photos, videos, etc.) back and forth between the smartphone/tablet and the TV.

The connection panel includes three side-facing HDMI inputs, as well as one component/composite mini-jack that requires the use of a supplied breakout cable. There's no PC input; one RF input is available to access the internal ATSC and Clear-QAM tuners. For network connectivity, you can choose between wired Ethernet and built-in WiFi. An SD card slot and two USB ports are available for playback of digital media files. The USB ports also support the addition of a USB camera for Skype and other apps, as well as a USB keyboard for easier text entry. (The GT/VT models have four HDMI inputs, three USB ports, and a PC input.)

The TC-P55ST50's setup menu includes most of the picture adjustments we like to see, with a couple of omissions. As I mentioned above, this model lacks the THX certification you get in the GT/VT lines; consequently, this TV lacks the THX picture mode that's designed to be the most accurate out of the box. You can choose between five picture modes: Standard, Game, Vivid, Cinema, and Custom. As in past models, only the Custom mode grants you access to important Pro settings like RGB high/low controls for white-balance adjustment, panel brightness (low/mid/high), and gamma adjustment (six presets). The Pro menu also includes black extension, contour emphasis, and AGC controls that I chose to disable when using the Custom mode. The biggest omission is an advanced color-management system that allows you to individually tailor the six color points, but this wouldn't prove to be a huge concern, as the color points looked quite accurate. Panasonic's Motion Smoother function, first introduced last year, is available for those who desire a de-judder control that produces smoother motion with film sources (it also slightly improves motion resolution - more on that in the Performance section). Panasonic still includes the option to output 24p film sources at either 48Hz or 60Hz. The 48Hz option repeats each film frame twice for a slightly less juddery image than 60Hz. However, 48Hz also creates highly distracting flicker, so I don't recommend it. This model doesn't include the more desirable 96Hz mode that's offered in the VT Series.

In the 3D realm, the TC-P55ST50 is an active 3DTV that employs frame-sequential 3D technology, in which the TV alternately flashes a full-resolution left-eye and right-eye image. Panasonic's new 2012 rechargeable glasses (TY-ER3D4MU) communicate with the TV via Bluetooth, weigh just 27 grams, and have a new Quick Charge feature (a two-minute charge gives you three hours of use); the MSRP is $79.99 per pair. The 3D setup menu looks similar to last year's, and it includes 3D Adjustment to adjust the left-eye versus right-eye depth to produce a more desirable 3D effect, the ability to swap the left/right images if it seems like the depth perception is off, a diagonal line filter to remove jaggies, and the ability enable 2D-to-3D conversion and adjust the depth in three steps (minimum, medium, or maximum). In terms of picture adjustments, when the TV detects a 3D signal, it automatically switches to a 3D picture menu that provides access to all the video controls I listed above for 2D content.

The audio setup menu lacks any preset sound modes or advanced equalization. You get bass, treble, and balance controls, as well as a basic surround mode. The previous Bass Boost option is gone, probably because of the addition of a subwoofer. The AI Sound feature is designed to equalize the volume level across all channels and inputs, while Volume Leveler deals specifically with reducing level variations between the different inputs. Panasonic has added a Distance to Wall setting to adjust the low-frequency level based on whether the TV is on a stand (over one foot) or wall-mounted (up to one foot). The new speaker/sub configuration definitely adds a bit more meat to the mid and lower frequencies, resulting in a less nasal, tinny sound; however, I had to push the volume pretty high to get decent dynamics.

As I write this in early April, the VIERA CONNECT platform hasn't changed much from last year's implementation, although new features that were announced back at CES are supposedly coming within a month or so. (I hope to do a write-up on those at a later time.) The one improvement built into the ST50 and other new models is that VIERA CONNECT now uses a cloud-based architecture that speeds up the processes and allows for an unlimited number of apps to be added through the VIERA CONNECT Market. The ST Series does not utilize the dual-core processor found in the GT/VT models that allows for multitasking, or the ability to have multiple apps open at the same time. The basic VIERA CONNECT interface and navigation are still the same, and that's fine, because I consider this to be one of the cleaner, easier Web platforms out there. Premium services include Netflix, Hulu Plus, VUDU, Amazon VOD, CinemaNow, Pandora, YouTube, Skype, and the Social Networking TV app that lets you watch TV and navigate Facebook/Twitter simultaneously. The new YouTube interface is cleaner and quicker to navigate; plus, videos automatically begin in full-screen mode, which is a welcome change. As in past models, most of the picture adjustments I described above are available for VIERA CONNECT sources.

Performance
For the past few years, Panasonic has sent me a review sample from the G or GT Series, all of which were THX-certified TVs. In fact, my reference plasma is still the TC-P50G25 from two years ago, and it was interesting to compare that older THX-certified model with this new ST model. In many respects, the two TVs offered similar performance, with a key caveat: the older G25 offered its best performance in the THX mode with minimal tweaking, while the new ST50 benefited from calibration within the Custom mode.

Read more about the Panasonic TC-P55ST50's performance on Page 2.

Of all the preset picture modes, the TC-P55ST50's Cinema mode looks the best (the Standard mode is surprisingly dark). Be warned that Motion Smoother is now turned on by default in this mode, so if you don't like that soap-opera effect with film sources, you'll want to turn go into the Advanced video menu and turn it off. Black level, brightness, and color are all respectable in this mode, but the Warm2 color temperature is a bit green, and the gamma is too light. You can't adjust either of these parameters in the Cinema mode, which is why I switched over to the Custom mode to perform a more advanced calibration, and was happier with the results. I switched gamma from the default 2.2 to a seemingly more accurate 2.6, I went with the "mid" panel brightness, and I performed some eyeball adjustments to the RGB controls to dial in a more neutral color temperature. After performing these tweaks, I settled in with my usual assortment of BD/DVD demo scenes and HDTV content from DirecTV.

First off, the TC-P55ST50's black level is excellent, which allows it to render a wonderfully saturated image in a dark room. (The GT50 model uses the same Infinite Black Pro panel, while the top-shelf VT50 uses the Infinite Black Ultra panel.) Thankfully, I saw none of the odd brightness fluctuations that plagued last year's Panasonic GT30 plasma. The ST50 produced a deeper shade of black than my reference G25 - not significantly deeper, but deep enough that you could obviously see the difference in a side-by-side comparison. Combine this great black level with very good image brightness, and you get a rich-looking image with outstanding depth and overall contrast. The ST50 certainly isn't LCD-bright and probably isn't the ideal choice for an extremely bright room; however, in my family room with the window blinds open, the picture had ample brightness to produce vibrant HDTV and sports content during the day. The TC-P55ST50 also did an excellent job rendering fine black details, and its overall level of detail with HD sources was very good. Beyond the mildly green color temperature that I was able to correct, I had no issues with the TV's color performance. All of the color points looked close to reference standards, and skin tones were neutral (more natural-looking than those of the G25, I might add).

Motion blur isn't really a concern with plasma technology, but I ran through the motion-blur tests on my FPD Benchmark BD anyhow. The TC-P55ST50 cleanly rendered all of the motion-blur patterns and did not exhibit the occasional ghosting effect I see with 120Hz/240Hz LCDs. With Motion Smoother disabled, the TV produced clean lines to HD720 in the Resolution test pattern. With Motion Smoother enabled, the lines were clean to HD1080. The difference was small enough that I was content to leave Motion Smoother turned off, since I don't like its smoothing effects with film sources. I will say that the Weak Motion Smoother mode is subtle enough to be tolerable. In other processing news, the TC-P55ST50 passed all of the 1080i tests on the HD HQV Benchmark BD, and I did not notice jaggies or other artifacts with real-world 1080i signals.

For my 3D tests, I ran through my standard demos from Ice Age: Dawn of the Dinosaurs (Chapters 3 and 9), Monsters vs. Aliens (Chapters 12 and 13), and Monster House (Chapters 6 and 7), plus assorted DirecTV 3D content. Like its 2D counterpart, the TC-P55ST50's 3D image has excellent contrast and rich color. The 3D depth was impressive, and the level of detail was very good with both Blu-ray and DirecTV content. Light output was good for HDTV and movie-watching in a medium to dark room, but I found the Cinema and Custom modes to be a little dim for a bright daytime environment (the Game 3D mode is a slightly brighter alternative). In last year's GT30, I could crank up the light output by setting the panel brightness to high in the Custom mode; this year, that change seemed to have little effect beyond slightly altering the color temperature. In terms of 3D hardware, the lighter TY-ER3D4MU glasses are much more comfortable to wear for an extended period of time.

The Downside
The TC-P55ST50's image was sometimes noisy in darker scenes. The new GT/VT models reportedly have 24,576 steps of gradation, while the ST models have about half that, or 12,286 steps. (The UT/XT models drop to 6,144 steps.) When I put up the DVE gray-scale ramp, the transition from light to dark was not smooth; I saw more uneven steps than I've encountered on any recent TV I've reviewed. With real-world sources, that sometimes translated into noise, uneven transitions from light to dark, and color shifting in grays. Two of my favorite gray-scale demos are Chapter 10 in the Ladder 49 DVD (in which Joaquin Phoenix moves through a dark, completely smoke-filled room) and Chapter 5 of the Flags of Our Fathers BD (in which the soldiers sit on the ship's deck on a dark, foggy night). Both scenes exhibited color shifting in their grays. Interestingly enough, the new ST50 exhibited slightly less color shifting than the older G25; however, in certain dimly lit scenes from House on Fox's HD channel, the newer model revealed more noise and uneven gradations in backgrounds. By comparison, my living-room LCD (the Samsung LN-T4681) produced a cleaner picture in these same scenes. The lighter gamma in the ST50's Cinema mode also contributes to the problem, making low-level noise more obvious in darker areas of the scene. I was able to lessen the visibility of the noise in the Custom mode by setting a darker, more accurate gamma. I also upped the noise reduction to strong, which helped but didn't completely solve the problem. This wasn't an ever-constant issue with all sources, but I did see more noise than I'd prefer.

The TC-P55ST50's handling of SD content is average at best. Upconverted images looked a little soft, and the TV was somewhat slow to pick up the 3:2 cadence in film sources, so I noticed jaggies and moire in my demo scenes from Gladiator and The Bourne Identity. The TV also failed to detect most of the assorted cadences on the HQV Benchmark DVD. For the best performance, you might want to let your source devices or an external processor handle the upconversion process.

The Infinite Black Pro panel effectively reduces glare off the screen while allowing blacks to look darker during the day; however, it's still a reflective screen, which can present problems when trying to watch darker content in a well-lit room. Be mindful of the position of lamps and other light sources in relation to the TV.

With 3D content, I was surprised by the amount of crosstalk I witnessed - surprised because, in my experience thus far, plasma does the best job of keeping crosstalk to a minimum in active 3D displays. That's not the case here. I wouldn't say the TC-P55ST50's crosstalk is excessive, but it occurs with enough consistency to earn it a mention here. Also, Panasonic has opted not to include any 3D glasses with the ST50. While the $80 asking price of the TY-ER3D4MU is lower than previous glasses, it still adds up if you want to buy glasses for multiple family members.

Competition and Comparison
Compare the TC-P55ST50 to its competition by reading our reviews of the Samsung PN59D8000, LG 50PZ550, and Sony KDL-46EX720. You can get more information about all of the 3D-capable TVs we've reviewed here.

Conclusion
In my book, you still can't beat plasma when it comes to getting the best combination of features, screen size, and performance for the price, and Panasonic has set the 2012 bar high with the new TC-P55ST50. This 55-inch plasma TV currently has a street price around $1,550; a similarly equipped model in the LED camp could cost you $1,000 more than that. There's also the not-insignificant fact that the TC-P55ST50 serves up a very attractive HD image, with an excellent black level, good brightness and detail, and natural color. If you're shopping specifically for a 3DTV, you can find better 3D performers on the market, but the TC-P55ST50's 2D performance is excellent.

I must add, though, that I'm intrigued by the step-up TC-P55GT50: It costs about $350 to $400 more than the ST50 (still a good value at this screen size), but it adds THX certification, the 24,576 gradation steps, the dual-core processor for multitasking, and more connection options. While I have not yet reviewed the GT50, its THX mode could mean a better-looking image right out of the box with little to no calibration, and the higher gradation number could mean less digital noise. It's at least worth a comparison of the two models to see if you find any potential performance improvements to be worth the step up in price.

Additional Resources
• Read more plasma HDTV reviews written by Home Theater Review's staff.
• Explore Blu-ray player options to pair with the TC-P55ST50.
• Find a soundbar in our Soundbar Review section.