Jurassic Park - Mixes & Myths

[dvdmike]

Did we ever have access to the theatrical audio for Lost World?

[spoRv]

I did my own rip of JP theatrical DTS with true DTS hardware and made only attenuation as needed for LFE and surrounds

So it was not a software conversion fault the fact surround and/or LFE levels needed to be changed on some releases... good to know!

[Turisu]

I've synced the cinema DTS of The Lost World to the UHD. I'll upload it in the next day or so.

[Wisp of Smoke]

Far field mixes are fine at home. There were people absolutely adamant that a theatrical far field mix would destroy your speakers and it would be dangerous to even consider including them on home releases. Then Criterion released The Game with near and far field mixes.

Turisu have you heard the LD tracks for The Matrix? It's strange that you claim the BD TrueHD tracks to be the closest as that was the release that was considered weaker than previous releases, or are you referring to the remastered BD?

Also to go back to an earlier point Cinema DTS does not have a matrixed subwoofer channel. It is stored in the surround channels and is low-pass filtered for playback. As a result the subwoofer carries the LFE information and any low frequencies contained in the surround channels, which is why the waveform for LFE channels looks 'busier' on C-DTS tracks. By contrast the waveform of surround channels will look different, but as long as the extraction is done properly the resulting sound will be the same as bass is non-directional (indeed if listening on a satellite surround system all low frequencies will be sent to the subwoofer anyway).

That's some interesting info about the LFE. So I wonder what process they use that
renders the 'less active' LFE channel we see in home mixes.

As for The Matrix; the mixes I've compared (DVD AC3, BD TrueHD, BD AC3, BD AC3 Core, UHD AC3, UHD AC3 Core) all have a boosted centre channel compared to the cinema DTS except for the BD TrueHD 5.1 which is just a slightly less dynamic version of the theatrical mix. I haven't got the LD audio but I was led to believe it was the same as the DVD. If anyone has it I'd be happy to compare .

I have a theory that am pretty sure explains why Cinema DTS mixes may on occasion have a little more LFE content compared to their original 5.1 mixes that later show up on LD, DVD, bluray, and if we're really lucky, 4K.

As we know, the cinema DTS system piggybacks the LFE channel in the discrete surround channels and the theater decoder extracts the LFE back into it's own channel for the subwoofer.  

The catch here is most 5.1 mixes are mixed the same regardless of what discrete delivery service is going to be used.  Meaning- the mixer could also mix lower frequency information into the split surround channels. And that is not an uncommon thing in original theatrical mixes.  But with the DTS theatrical system, the LFE channel is extracted from the surrounds, which means there may be additional low frequency information also extracted that had not been mixed with the LFE channel in mind.  This side effect is pretty benign, but on occasion you would certainly see some distinct differences if you compared what in this case I'll call the original discrete 6 channel mix vs the DTS 5.0 discrete system with it's LFE extraction method back to 5.1

[zoidberg]

I'm pretty certain during the encoding process any low frequency content in the surround channels would be treated so as to sound correct when decoding for playback. Don't forget DTS's subwoofer level was changed to match the 10db in-band gain used by the other discrete formats, without a corrective measure this would have affected the surrounds' low frequencies yet again.
There is this tendency to treat Cinema DTS as some tinpot process that was all over the place because of the way the subwoofer channel is stored in the surrounds. The baby booms on 70mm were stored in exactly the same way and carrying it over to DTS meant the CD-ROMs could store more audio per disc. It is also the only available sound format for new 70mm prints (under the new name Datasat).

[Wisp of Smoke]

Hi Zoidberg,

Oh I agree and your note of the 10 band gain is a good one. I for one certainly do not consider DTS a tinpot process. My primary point is having a mix which already had some lower frequency info in the surrounds would not be uncommon. And if the surrounds were not filtered before the LFE insert the effect would often be very minimal - to the extent of being considered benign. That being said, I *would* expect to see low end differences if doing direct A/B comparisons between the discrete 6 ch original and one where the LFE was stored in with the discrete surrounds. Again - those being very small differences when they would happen.. and not something anyone normally would ever detect outside of something as rigorous as direct a/b testing

[zoidberg]

As I mentioned somewhere else the waveforms of a discrete 5.1 mix and a 5.1 mix 'extracted' from a Cinema DTS file will look different as the LFE channel will look busier due to the additional low frequencies originally belonging to the surround channels. Likewise the surrounds will look weedier due to the filtering. As low-frequencies are non-directional the 2 mixes should sound similar and indeed there is a monitoring stage, before the printmaster encode is made where the mix can be checked. I would like to think that where the subwoofer channel is expecting a gain of, for example's sake 10dB in the b-chain then the low frequency content of the surrounds will be attenuated by the same amount during encoding in order to sound correct upon playback.
I suppose what I'm trying to say is that the proof of the pudding is in the eating and the mix should be judged on how it sounds, not how it's waveforms look in editing software.

[Wisp of Smoke]

I suppose what I'm trying to say is that the proof of the pudding is in the eating and the mix should be judged on how it sounds, not how it's waveforms look in editing software.

Agreed. And a perfect analogy.

[Turisu]

It can't be denied that the most important aspect of a mix is how it sounds. But by comparing waveforms we can actually dispel much of the false information that's been spread over the net about these mixes usually by people who have done nothing but their own subjective listening tests.

It's been argued by some that Jurassic Park's LD DTS has theatrical LFE. Or that the first DTS DVD had defective LFE. Or that The Matrix BD 5.1 is a neutered remix. All proven untrue.

Also keep in mind I'm not trying to find the best sounding mixes here. I'm just interested in to what extent home video mixes are altered from their theatrical originals.

[zoidberg]

Please tell me you are actually comparing these mixes aurally, on a surround system preferably at a decent volume, and not just looking at waveforms on adobe software which may or may not be presenting the audio accurately