Significantly harder to peg, however, is the quality of the Dolby TrueHD 5.1 audio. Unfortunately, the Toshiba hardware will not pass the TrueHD surround channels at this resolution, just 2.0 stereo (a warning message appears on screen when you try to select the TrueHD 5.1 informing you of this limitation), and even the stereo is just downmixed LPCM. If Dolby Digital-Plus equates to the best standard DTS presentations, TrueHD should - in theory, when the hardware is ready to handle it - be comparable or even greater to the quality you'd expect on an even higher resolution DVD-Audio disc. There's a good reason for that - TrueHD takes advantage of the same "lossless" MLP encoding process upon which the DVD-Audio format was based. However, with the current hardware limitations and without the same complete surround presentation as you get with the Plus mix, it's very difficult to make an accurate comparison. Unfortunately, we'll have to wait for fully compatible HD-DVD players and surround receivers to know just how good TrueHD can be.