The two-tiered THX certification system for A/V components reminds me of canned black olives: the smallest ones you can buy are labeled "large," and they range upward from there to "jumbo," "colossal," and, I suppose, "gargantuan." Similarly, the lowest THX rating, THX Select, is awarded to very good midprice gear, while THX Ultra2 (an upgrade of plain old THX Ultra) is reserved for high-performance, premium-price gear with state-of-the-art features.
THX Ultra2 differs from its predecessor by mandating full 7.1-channel playback capabilities for Dolby Digital Surround EX and DTS-ES soundtracks, which add a back surround channel for one or two speakers centered behind the listening position. To be certified as THX Ultra2, a receiver has to provide not only decoding for 7.1 channels and processing to derive 6.1- or 7.1-channel playback from 5.1-channel sources, but also seven discrete amplifier channels as well as "boundary gain compensation" to help match a subwoofer's output to the room acoustics regardless of its placement. And THX Ultra2 requires a receiver to have wideband component-video switching to handle signals from a progressive-scan DVD player or a high-definition TV (HDTV) tuner without picture degradation.
Pioneer has long been an enthusiastic supporter of the THX program, so it's not surprising that the VSX-49TX, the latest flagship of its premium Elite line, is one of the first THX Ultra2-certified receivers on the market (the other is the Pioneer VSX-47TX). On the face of things, it's a fairly conventional big high-end receiver with all the goodies we'd expect of such a beast, including lots of power - 130 watts each for all seven channels. Besides Dolby Digital Surround EX and DTS-ES Discrete 6.1/ 7.1-channel surround decoding, there's also Dolby Pro Logic II and DTS Neo:6 processing to play stereo and four-channel Dolby Surround-encoded recordings and broadcast sources as if they had 5.1 channels, plus extensive proprietary digital signal processing (DSP) ambience modes. There are gobs of input/output options, including three wideband component-video inputs, a phono input, and a Dolby Digital RF input for a laserdisc player.
