home 7.1 releases - general discussion

[spoRv]

To whom it does not know: the home 7.1 channel movie releases include Blu-ray and UltraHD Blu-ray as physical media, and web streaming and download; there were no DVD, LD or other media AFAIK; albeit on theaters there were two 7.1 formats - SDDS with left, left extra, center, right extra, right, surround left, surround right, LFE, and Dolby Surround 7.1 with left, center, right, surround left, surround right, surround back left, surround back right, LFE - only the latter channel configuration is used at home. Not sure about DTS 7.1 and if any movie release in DCP used the SDDS speaker configuration. From now on, 7.1 = Dolby configuration - three screen channels, four surround channels, plus LFE.

OK, back on track: if a title had not a 7.1 (or immersive sound) theatrical release, the home version with 7.1 is not faithful to the theatrical mix, hence the extra back surround channels were created using the left and right surround (and back center when available on 6.1 releases).

According to Blu-ray stats - http://www.blu-raystats.com/Stats/Stats.php (yes, I know it's not updated, but I have found only this for now) there were (up to around March 2018) 839 releases with 7.1 channels, or 6.61%; only 0.46% with 6.1, around 70% with 5.1 and 5.0, 12% stereo and 6% mono; until now more 7.1 releases came - as well as with other audio tracks, in particular Dolby Atmos and DTS:X, so I guess the percentage would be not noticeably different.

I made my homework, and according to some sources, there are around 800 titles on BD/UHD-BD with 7.1 track - remember, that 839 was referred to releases, with multiple ones referring to a single title.

Less than 250 of them were released in theaters with immersive sound (Dolby Atmos, DTS:X or Auro3D) and around 50 exclusively on Dolby Surround 7.1; then, about 500 titles have "created" back surround!!!

Of these 500:

• a dozen or so had 6.1 theatrical release
  
• at least 200 were released prior 2010, when Dolby Surround 7.1 came out
  
• the others may have used DCP 7.1 theatrical mix
  

So, we are left with AT LEAST more than 200 titles out of 800 - a whopping 25% - with created back surround; this would reduce the overall percentage to around 5%.

I'm sure that also a lot of 5.1 releases are not true to the theatrical versions too, still the percentage is overwhelming - 7.1 are less than 1/10th of 5.1

Conclusion: there is no rush to get a 7.1 sound system if you already have a good 5.1!

Further info:
Posted by Audyssey Labs in June 2012 (https://audyssey.zendesk.com/hc/en-us/ar...l-sources-):

There are almost no instances of 7.1 content that is produced that way for the movie.  The so-called 7.1 Blurays take the original 5.1 movie mix and use a matrix method to generate the additional Back Surround channels.

Posted by F. Hudson Miller in March 2013 - http://www.film-tech.com/cgi-bin/ubb/f16...28/p1.html:

We may on occasion generate a 7.1 if the film has only been mastered in 5.1 (that usually just some minor re-channeling)

and just two treats to end:

Smith employed DTS Neural Upmix software to remix "The Rocky Horror Picture Show" from 5.1 and other elements to 7.1 for BD release this year

Steven Spielberg's 1975 hit will come home in "digitally remastered and fully restored" form with an upmixed 7.1 DTS-HD MA soundtrack

[dvdmike]

Most at home were remixes, 7.1 along with Ex were not big hits that Dolby expected

[zoidberg]

On a slight tangent here but it's worth remembering that unless a release includes a 2.0 matrixed surround soundtrack then the discrete 5.1/6.1/7.1 will be compromised to accommodate being downmixed to 2.0, which can seriously weaken the imaging of the soundfield.

[spoRv]

I think it's not the case when talking about DTS-HD MA and Dolby TrueHD - while it could be for Dolby Digital Plus and/or DTS-HD HRA.

AFAIK both contain the 2.0 mix as "base layer", where the other layers are added on top of this - so 2.0+3.1 to get 5.1, 2.0+3.1+2.0 to get 7.1, and lastly immersive sound layer.

What you are talking about was the norm with DVD and Dolby Digital 5.1 - DTS may be safe, though, as it was only an optional codec; IIRC all DVD with DTS track included also a DD track.

[zoidberg]

So far as I can tell including an embedded 2.0 track is optional for DTS-MA (at these expense of file size and bitrate), I can't see anything about it for Dolby TrueHD

[stwd4nder2]

In my setup, I noticed a difference when upgrading from 5.1 to 7.1. In 5.1 the effects from the rears would sound like they were coming from speakers in the corners, whereas adding those extra 2 speakers gave it a more natural sound and felt more like things were actually happening behind/around you.
I would highly recommend upgrading if you can. I just hope my future upgrade to atmos makes as big a difference.

[zoidberg]

I always found it weird that there were more speakers behind you than in front with 7.1. FWIW I had a 6.1 setup for years but went back to 5.1 when I moved as the SB speaker was no longer practical, can't say I miss it really. What I really need to do is install/set up my second subwoofer for bass 'reinforcement'

[spoRv]

Indeed... always following the (sometimes wrong) Dolby direction: 3/2/4.1 instead of 5/2.1 as SDDS, and link the dialogue to the center channel.

These to me are two faces of the same medal: Dolby can't follow Sony's direction - even if the latter collaborated actively with it, for example with Pro Logic digital decoders - so instead of putting (back) the left center and right center channel, it decided to add a back channel; then of course it was forced in a way to add another back channel - cheaper than admitting "wait! we were wrong... we did not think that humans have two ears that capture sound much better in the front, so we must revert to five front screen channels!"