Theatre and Home Theatre Audio Mastering.... are they different? How different, and how often?

[dlaloum]

Hi Folks,

So first some background... I started being interested in HT in the mid 1980's - I worked for a couple of years at the first HT specialised store in Melbourne at the time.

Going back to 1985, the HT material available was either Laserdisc or VHS, delivering mostly stereo (AC3 came a bit later with DVD's) - what was happening at the time, is that the studio's would simply copy the stereo Dolby Surround (matrixed) tracks used for theatre releases, onto LD or VHS... which meant we had exactly what theatres recieved and it was up to us to decode it and replay it.... we started with rear speakers, and when AC3 came out with its seperate channels including LFE, speakers proliferated and subs started to be a major thing.

For at least the first 2 decades, it seems to me that most if not all the movies released, carried the standard theatre sound track.

Moving to the current state of play, it appears to some releases today, actually have the mastering engineer remaster the audio for the HT release, and possibly even seperately master base AC3 layers vs TrueHD/Atmos etc.... so we could be looking at a situation where there might be 3 or 4 differing masterings of the same material.

So the first questions is: How common is this? How many movies still get the theatre mastered soundtrack? How many movies get a seperate mastering for home releases or even seperate masterings for seperate sound formats!

The next question is, how do TV shows get mastered? Do they keep to the theatre conventions? Reference Levels? - if not, is it a free for all? (the way it has always been with music?)

When considering the best way to set up a HT - these are all relevant questions... yet I see very little discussion of it, and perhaps very little awareness of it (!?).

Thoughts?

 

[dlaloum]

For further current information, here is the current Dolby Professional Atmos Specification :

https://professional.dolby.com/siteassets/cinema-products---documents/dolby-atmos-specifications.pdf

Salient Points:

Front "Screen Speakers"
Level req's 105db SPL continuous
Frequency Range 40Hz to 16kHz +3 / -6 db
Frequency Response 80Hz to 16kHz +/- 3 db (not clear what the difference in intent between range and response is...)


LFE
The LFE is also the "Screen Subwoofer"
It is specified at +10db SPL relative to the center channel
Frequency response 31.5Hz to 120Hz +/-3db

Surround
Level req's 99db SPL continuous (amp should have additional 3db headroom)
(Surround Array 105db)
Frequency response 40Hz to 16kHz (+3/-6db)
If bass management is used crossover should be 90Hz or lower
Surround speaker frequency response should be +/- 3db @<130Hz
Where crossover frequency is higher than 80hz multiple subwoofers are recommended (localised bass!?)

This is of course relevant to Theatres.... and the Theatre masterings of the Audio - but how much relevance does it have in the home?

 

[Audio Science Pal]

Good questions. Looking forward to reading the responses.

 

[Chrispy]

I'm more interested in what I perceive as a divergence with typical music audio production. Seems for movies we have at least a bit more adhered-to scenario, but not completely.

 

[dlaloum]

I'm more interested in what I perceive as a divergence with typical music audio production. Seems for movies we have at least a bit more adhered-to scenario, but not completely.

Yes the standards around movies have allowed for things like Audyssey focusing their perceptual loudness function (DEQ) around the standard specified reference level - and it works well...

Until you apply it to music or TV, where there is no standard, and then you try to turn it up or down and it becomes a bit of a mess.

 

[Chrispy]

Yes the standards around movies have allowed for things like Audyssey focusing their perceptual loudness function (DEQ) around the standard specified reference level - and it works well...

Until you apply it to music or TV, where there is no standard, and then you try to turn it up or down and it becomes a bit of a mess.

Then again all my Audyssey options include a variance for DEQ in relation to input. Does help when there is a standard of sort to base things on.

 

[Soundmixer]

For at least the first 2 decades, it seems to me that most if not all the movies released, carried the standard theatre sound track.

This is not correct. For the last two decades, most movie releases (at least the big box office releases) have had tracks mixed especially for the home environment. All of the major studios have done this, with Disney leading the way back in 1998.

Moving to the current state of play, it appears to some releases today, actually have the mastering engineer remaster the audio for the HT release, and possibly even seperately master base AC3 layers vs TrueHD/Atmos etc.... so we could be looking at a situation where there might be 3 or 4 differing masterings of the same material.

There are at least two masters made. One for disc, and one for streaming. I have not heard of any studio doing 3 or 4 different masterings; that is not necessary. You don't need to do separate mixes for Atmos and non-Atmos setups; the renderer in the decoder does that work for you. If you don't have an immersive setup, the renderer will ignore the metadata that controls the positioning of the objects, and you get the TrueHD core.

So the first questions is: How common is this? How many movies still get the theatre mastered soundtrack? How many movies get a seperate mastering for home releases or even seperate masterings for seperate sound formats!

Not many movies get released on disc that carry the theatrical soundtrack. Smaller independent movies may carry over the theatrical soundtrack to disc, but that is about it. Theatrical soundtracks are overwhelming when played back in a small room. They are also too bright, and FAR too bass-heavy.

The next question is, how do TV shows get mastered? Do they keep to the theatre conventions? Reference Levels? - if not, is it a free for all? (the way it has always been with music?)

Television shows do not use theatrical parameters for their soundtracks. They are mixed and mastered at levels much lower and in much smaller rooms. They don't have nearly the level of dynamics that a theatrical track has, and therefore place far less demands on the user's playback equipment.

 

[dlaloum]

This is not correct. For the last two decades, most movie releases (at least the big box office releases) have had tracks mixed especially for the home environment. All of the major studios have done this, with Disney leading the way back in 1998.




There are at least two masters made. One for disc, and one for streaming. I have not heard of any studio doing 3 or 4 different masterings; that is not necessary. You don't need to do separate mixes for Atmos and non-Atmos setups; the renderer in the decoder does that work for you. If you don't have an immersive setup, the renderer will ignore the metadata that controls the positioning of the objects, and you get the TrueHD core.



Not many movies get released on disc that carry the theatrical soundtrack. Smaller independent movies may carry over the theatrical soundtrack to disc, but that is about it. Theatrical soundtracks are overwhelming when played back in a small room. They are also too bright, and FAR too bass-heavy.




Television shows do not use theatrical parameters for their soundtracks. They are mixed and mastered at levels much lower and in much smaller rooms. They don't have nearly the level of dynamics that a theatrical track has, and therefore place far less demands on the user's playback equipment.

Thanks for that response... note that my reference to the first 2 decades is referring to the 1980's and 1990's.... which is when some of us first started into "home theatre"...

So my assumptions on mastering are dated...