OTHER TECH

Where's the 7.1?

Q. I spent big money for a 7.1-channel speaker setup, but all the new high-def discs have 5.1-channel soundtracks. So, where are the 7.1 discs? Elias J. Vujovich / Southington, OH

A. At the moment, there are only a limited number of 7.1-channel Blu-ray Disc titles available - around 20, by my last count. Of these, half are multichannel PCM discs, and the other half have 7.1-channel DTS-HD Master Audio soundtracks. Dolby TrueHD also supports 7.1-channel Blu-ray soundtracks, but titles that make use of that format's full channel allotment have yet to appear outside of Dolby's own demonstration discs.

While it's a sure bet that we'll see more 7.1 on Blu-ray in the near future (six additional titles are scheduled for release this summer, including the horror film The Eye and Oliver Stone's The Doors), there's no reason why those back speakers in your system should remain idle. A decent number of DVD soundtracks have been encoded in either Dolby Digital EX or DTS-ES - technologies that provide an additional matrixed (or in the case of DTS-ES, either discrete or matrixed) surround channel, bringing the total channel count up to 6.1. (In a 7.1-speaker system, that extra mono surround channel gets distributed to both of the back speakers.) Many recent-vintage receivers and processors will decode DD EX and DTS-ES soundtracks. A number of them also offer Dolby Pro Logic IIx and DTS Neo:6 processing, both of which produce a 6.1- or 7.1-channel output from a standard 5.1-channel or stereo source.

5.1 Fears

Q. I'm happy with my current 5.1-channel speaker system, and notice that most of the systems you review are also 5.1-channel ones. Is there an advantage to upgrading for the new lossless audio formats on Blu-ray Disc if I still only have a 5.1 setup? What will the receiver do if it receives a 7.1 track when there are only 5.1 speakers attached to it? John Fultz / West Chester, OH

A. It will explode. (Just kidding!) The lossless 7.1 soundtracks on Blu-ray Discs are completely backward compatible with existing 5.1-channel speaker systems. For example, if a Blu-ray player sends a lossless 7.1-channel Dolby TrueHD bitstream to a receiver via an HDMI connection, the receiver's built-in decoder can downmix the 7.1 soundtrack to a 5.1-channel version. It does this by combining the back and side surround information in the soundtrack, creating a set of "composite" left/right surround channels. And with DTS-HD Master Audio, the format's architecture incorporates a "core" 5.1 version of the soundtrack - even when that soundtrack contains 7.1 channels. (The DTS decoder ignores the extra channel data.)

Even when you're using a Blu-ray player to decode soundtracks, the same basic situation applies. But in this case, the player's decoder performs a 7.1- to 5.1-channel downmix (or in the case of DTS, extraction of the core 5.1 soundtrack) before converting the decoded signals to multichannel PCM to be sent out via HDMI, or to analog format for output over the RCA-jack audio connections.

Dream Recorder

Q. I recently bought a DVD recorder and found that it doesn't record Dolby Digital soundtracks. I watch a lot of concerts on satellite TV, and find it disappointing that I can't record the 5.1 sound to DVD. Is there a standalone DVD recorder that does what I'm looking for? Keith Cinnamon / Regina, Saskatchewan

A. Unfortunately, standalone DVD recorders capable of capturing Dolby Digital 5.1-channel sound from DirecTV and Dish Network satellite-TV channels don't exist. But both satellite providers offer receivers with built-in DVRs that can record programs with 5.1 sound. You won't be able to archive those same recordings to DVD, but you can hang on to them for a while - at least until the DVR's hard drive fills up.

DLP SOS

Q. I think I recently read that DLP technology was a no-show at this year's Consumer Electronics Show, and that meant it was going away. If that's true, would it be wise for me to buy a DLP TV? Ron Pant / via e-mail

A. DLP isn't dead. In fact, it's very much alive. Major TV manufacturers like Samsung and Mitsubishi still make DLP rear-projection sets, and several front-projector companies are developing new models that use the technology. But there's no denying that the wide popularity of flat-panel LCD and plasma TVs has taken a big bite out of DLP sales - the likely reason why key supporters such as Toshiba opted to ditch DLP last year in order to concentrate on flat-panels. As for buying a DLP TV, why not go for it? These sets can deliver outstanding picture quality, and even if the technology ultimately does drift away, large, established companies like Samsung and Mitsubishi should provide technical support for their DLP products well into the future.