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Theater Mix vs. BD Mix

Excepting Imax, it still seems the vast majority of theater releases are in Dolby Digital (or DTS, with Sony's variant being increasingly rare). Even with the introduction of DD EX for Star Wars: The Phantom Menace seems to have done very little to change the standard 5.1 mix. The standard multi-channel mix, then, seems to be 5.1, with occasional titles matrixing the rear 6th channel. Dolby doesn't indicate anything more sophisticated on their site, and the DTS products seem geared toward BD authoring as compared to theater mixes.

So is that rare "7.1" mix found on a handful of BDs even worth the bother if in fact the source was a 5.1 mix? The promise of 7.1 discrete channels seems more a marketing feature than one that will ever be realized in the software.

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Replies to This Discussion

Permalink Reply by Kieran Coghlan on October 13, 2009 at 8:54pm: Agreed! A thousand times agreed. Now we have "height" channels. ugh.; ▶ Reply to This

Permalink Reply by Chris Eberle on October 14, 2009 at 4:17am: A movie soundtrack is printed in an optical strip along the edge of the film itself. This small space limits it to Dolby Digital or DTS at a fairly high rate of compression. I believe the bitrate is actually lower than on DVD.

Of course with digital cinema this limitation does not exist. I believe newly-equipped digital theaters are using uncompressed PCM.

All the more reason to invest in a good home system and avoid the movie theater!; ▶ Reply to This

Permalink Reply by J. Andrew Yang on October 14, 2009 at 6:33am: It would be interesting to find out what the path is between the sound recording and the theater versus BD.; ▶ Reply to This

Permalink Reply by John E. Johnson, Jr. on October 15, 2009 at 10:26am: Even though the commercial theater may be 5.1 and the BD is 5.1, it will still sound different because the commercial theater uses so many surround speakers, and you are hearing the sound from the one nearest to where you are sitting, plus the sound from the others a bit delayed because they are farther away. As to 7.1, I don't care if the commercial theater uses it or not. 7.1 on a BD in my home theater is fantastic.; ▶ Reply to This

Permalink Reply by J. Andrew Yang on October 15, 2009 at 10:48am: So does that mean JJ is arguing more for a DD EX solution over a discrete 6.1/7.1? Or more currently DD IIz / Audyssey DSX.; ▶ Reply to This

Permalink Reply by vikrant shinde on October 16, 2009 at 11:42am: What jj said was correct because in theater's there is a delay of 100ms where as in our house it is standard 40ms . so j. yang u really dont have to worry about that just enjoy the sound in ur home.....; ▶ Reply to This

Permalink Reply by Jeremy Anderson on December 13, 2009 at 4:16pm: Because of the way mixes are done for the theater, 7.1 from 5.1 tracks typically works really well to recreate the sound you get in the theater from speaker arrays. For instance, if a sound is mixed 25% in the left surround and 75% in the right, in a theatrical environment the speaker arrays will phantom image behind you and to the right, not only because of the speakers directly to your left and right but because of the other speakers in the array that are behind you. This is even more true of theaters with rear speaker arrays that use EX/ES, as it helps to anchor the sound behind you a bit more. But here's the thing: The way the original mix is done is the same either way.

Where 7.1 succeeds in the home is to fix what 6.1 home systems failed at. Too often, the 6th channel placed directly behind you would image in front of you due to perceived reversal of a single point source directly behind the listener. DPL-IIx Music mode tried to fix that by steering the sound such that it always came from the side surrounds as well, in varying increments depending on where the sound was meant to be steered. 7.1 fixes that by always steering sound so that it has multiple point sources, relying on between-speaker imaging to anchor the sound where it should be. This is the only reason 7.1 in the home exists, in my opinion. As to whether we need a discrete 7.1 mix done for a BD, of course not. If the mixer wanted a sound placed behind you in a 5.1 mix, he steered it accordingly in that 5.1 space, and 5.1-to-7.1 technologies such as DPL-IIx (when properly set up) do a very good job of recreating the intended placement, albeit using additional channels to compensate for the difference between your home theater space and the typical large theater space. The so-called 7.1 discrete mixes typically just mimic the behavior of DPL-IIx Movie's steering logic anyway, with the only real difference being that they can slap 7.1 discrete on the cover.

All that said, I'm clearly not a purist. I'm running a 9.1 setup with DPL-IIz Height right now, and am really enjoying the sound I get out of it. It's the closest I've heard to making my living room system sound like I'm in a very large theatrical space, and it works fantastically well with the lossless 5.1 tracks on most Blu-ray discs.; ▶ Reply to This