Posted October 16 2003 - 10:01 AM
Thanks for your input, John. Based on your experience in 800x600, I'm going to pick up Halo and give it a shot!
| but expecting to get DPL-II from something that does't have DPL-II encoded audio is like expecting to get five-speaker surround from a monaural recording. |
I disagree with this statement. A well recorded/mixed 2-channel recording can benefit from matrix surround decoding like DPL or DPL-II, even if the engineer had no intention of it ever being played through a matrix surround decoder. In FACT, one of the PRIMARY design goals for DPL-II was to increase it's capability of decoding into surround, recordings that were NOT particularly good for matrix decoding. For example, a TRUE mono recording, split 50/50 into a 2-channel stereo CD, would collapse entirely to the center channel when played through a DPL decoder. I think even a DPL-II decoder would collapse such a recording to the center channel, although I'm not sure. However, what DPL II does better is to take a stereo recording that would collapse MOSTLY to center via DPL, and spread it better accross the front and surround speakers, without sacrificing much of the original sound stage.
I have made 2-channel digital recordings with my choir in some very accoustically active cathedrals, churches and chapels. These recordings are almost entirely without engineering (no mixing/fading or messing with the L/R balance)... pretty much exactly what was recorded by TWO mics is what is on each of the 2 (L&R) tracks. When I play these CDs through my speakers in "effects off" (pure analog stereo for the receiver) it sounds awesome, and if I sit JUST in the sweet spot of the main speakers, I can even detect out of phase sounds that seem to come from behind me (echos off the chapel walls... one place had a 7 second decay time for the echos.) However, if I turn on DPL (or DPL II) decoding, it sounds AMAZING from not just the sweet spot, but many seats... all the echos (except those from the front of the sound stage -- where the choir stood) come from the rear speakers. And this was with a pure, 2ch recording, no surround intent or mixing at all.
Neither DPL nor DPL-II require intentional surround mixing in the source recording. The nature of matrix surround decoding is to take advantage of what is naturally a part of a good stereo recording (out of phase signals) and properly place them around a surround speaker layout.
So, if a game is designed well, sounds that are supposed to be from behind you, will be out of phase with the main sounds. In a 2 speaker arrangement, this will sound like the sounds are behind you, IF you are in the sweet spot. With DPL or similar decoding, those out of phase sounds will come out of the surround mono channel. Ghost Recon DOES have out of phase surround information. When I turn on DPL, gun shots from behind me come out of the rear speakers.
Now, DPL-II claims that it can also infer directional (L&R) cues for those out of phase sounds by comparing them to the main signal. Remember their claims of providing 5.1 sound from a stereo recording? Well, with Ghost Recon, DPL-II sounds almost the same as DPL. There's a slight difference across the front sound stage, but not much, and the surrounds are close to identical from dpl to dpl-ii. Based on Dolby's claims, and the strong accolades reviewers have given DPL-II, this was a disappointment for me. However, I attribute it to the fact that video game software is not a "natural" source (unlike a choir singing in a church) so there could be some subtle sound wave phase things that dpl-ii is looking for, that aren't there in a video game sound track.