The best sound came from the Sony BDP-S1, followed by the two Toshiba models (which tied for second place overall) and the Pioneer and the Philips (which tied for fourth).
Dissecting these players' audio support is a mess. If you thought DVD's sound terminology was arcane--with Dolby Digital, Dolby Surround, DTS Digital Surround, and PCM--you ain't heard nothing yet. To that jargon add Dolby Digital Plus, Dolby TrueHD, DTS-HD Master Audio, and Linear PCM.
To find out what all that will sound like to your ears, we attached each of the players to Pioneer's Elite VSX-82TXS audio/ video receiver and NHT's Classic series 5.1-channel surround-sound system. We configured the players to handle their own audio processing.
In the first two chapters of The Phantom of the Opera, we listened for the sounds of birds flying, the clatter of the crystals on chandeliers, and the strains of instruments in the orchestral score; all sounded crisp and clear on the Sony BDP-S1 and on the two Toshiba players. We compared the 5.1-channel Dolby Digital sound tracks; the Blu-ray version of this film lacks the HD DVD version's Dolby TrueHD track.
Linear PCM blew me away in informal tests I performed using the Blu-ray version of The Last Waltz, a 1976 concert film recorded in high-quality analog. As heard piped through our test setup, from either the Sony BDP-S1 or the Pioneer, the film's music hit me with the full force of a live rock concert; every inflection by the individual musicians was perfectly clear. The same Linear PCM sound track played through the Philips and Samsung players, and to a lesser extent the Panasonic model and the Sony PlayStation 3, sounded muffled and muddy.
Player Specs and Details
The three HD DVD models--Toshiba's HD-A2 and HD-XA2, and Microsoft's Xbox 360--clearly lead the way in integrating interactive features, including picture-in-picture video, persistent bookmarks you can view after ejecting a disc, and the capability to deliver future content via ethernet. This is not surprising, given that the HD DVD format requires players to have the necessary hardware for a minimum level of interactivity.
Annoying design problems among the players abound. All of the units we tested responded slowly to commands, but the Pioneer Elite BDP-HD1 and the Sony BDP-S1 were the worst; each of those models took more than a minute just to accept a disc. Sony gave the BDP-S1 power and eject buttons that are merely thin slivers of metal, placed so high on the front panel that they're difficult to get to if you've stacked another component on top of the player. Toshiba's HD-XA2 remote uses similar sliver buttons, making it frustrating to use. And the Panasonic DMP-BD10 requires you to lower its front flap--which conceals the drive tray and buttons--just to use the machine.
Toshiba's players had issues when we switched from the players to another HDMI input, and then back again. The HD-XA2 stopped, indicated that the resolution had been changed, and insisted on restarting the film from the beginning. The HD-A2 froze up entirely, and needed to be rebooted. Toshiba says it is investigating why this HDMI handshaking issue occurred.