[1] I’m not sure why you want to continue to assert a track is not an audio channel or object.
[2] Dolby’s own white paper on mixing with Atmos says that it comprises 128 tracks (5.1 or 7.1 or 9.1 channels taking up some of those tracks).
[2a] I understand that this is for mixing, and may not be the same as a “track” on a video file.
[2b] You say my use of the term “track” would make sense, but it’s incorrect.
[2C] However, Dolby themselves say that a track can be a channel or audio object (in the context of a session).
1. I've already defined what the term "track" means and that it's commonly used interchangeably with the term "channel". If you wish a fuller understanding, try this wiki page on "
Multitrack recording". The reason I "want to continue to assert a track is not an audio channel or object" is because to understand what Atmos actually is, we have to get away from the traditional thinking in terms of tracks and channels. You yourself have quoted various different minimum channels for Atmos; 7.1.2, 7.1.4, 9.1.4 and 9.1. Using the traditional concept of tracks and channels, only one of these could be correct or possibly two if we make the (false) assumption that there are two versions of Atmos with different channel counts. However, in reality the consumer and theatrical versions of Atmos both have the same number of channels and the different channel/speaker configurations you have quoted are actually ALL correct because the traditional concept of tracks, channels and speaker configurations doesn't work with Atmos (or other formats which employ audio objects). I had thought you were starting to understand this new paradigm, due to your "edit" in your previous post, but this latest statement indicates that you're still having trouble.
2. Yes Dolby's paper does say that, BUT (!) you must understand the purpose of that paper is to explain what Atmos is, the basics of how it works and therefore introduce the concept of "audio objects". Dolby has used the term "tracks" because that's the closest reference with which readers of the paper (sound engineers, DCP authors, etc.) are already familiar, in order to progress to an understanding of what audio objects are.
2a. Yes, it is for mixing but you don't seem to understand the consequences of that and therefore what the term "track" actually means in that context. And BTW, there is no audio "track on a video file" with DCP. DCP is a hierarchical "package" of files, the audio files/tracks (in an MXF wrapper) are stored separately from the video file (JPEG2000).
2b. I can't actually remember that quote/reference but the use of the term "track" would make sense in a certain context, with a certain meaning. If you applied it outside of that context then it would be incorrect. Case in point:
2c. No, actually Dolby themselves did NOT say that! What Dolby actually stated was: "
Thinking about audio objects is a shift in mentality compared with how audio is currently prepared, but it aligns well with how audio workstations function. A track in a session can be an audio object, and standard panning data is analogous to positional metadata." - Dolby were deliberately very specific about the context and meaning of "track" here, precisely to avoid confusion and incorrect assumptions. A "session" is the ProTools name for a project file (effectively a mix or sub-mix/stem) and ProTools uses the term "track" to mean "channel". So in this context a track cannot be "a channel or audio object", a track IS a channel and that channel can be assigned as an audio object or mixed to the "bed". Dolby is therefore stating that up to 128 of the 1,000 or so channels in a mix can be assigned as "audio objects", while the others would be assigned/mixed to the "bed".
I realise that much of this could easily be seen as just semantics and that I'm arguing about some irrelevant definition/s of a rather ambiguous term just for the sake of arguing. However, that's NOT the case! To understand what Atmos actually is and avoid incorrect/inapplicable assertions about channels and speaker configs, then one has no choice but to understand these "semantics" because they define the difference between Atmos (and other audio object formats) and what went before.
[1] In the case of the Living Stereo 3.0 SACDs, RCA claims that playing them in 3.0 with a center channel more precisely defines the placement of the instruments in the center of the soundstage because the recording was made in three channels with a symphony orchestra with a mike on left, right and center.
[2] You could mix it to stereo and just have the phantom center serve, but having a separate channel covering the center provides more interior definition of sound sources in the middle--
[2a] woodwinds would be spread better, rather than just in an undifferentiated middle.
1. Yep, that's marketing gumpf! No one has (or would) record a symphony orchestra with 3 mics (Left, Right and Centre) for more than 60 years. The results would be poor.
2. Having a dedicated centre channel, can provide a more defined/anchored centre position, that's all though!
2a. No, woodwinds would not spread better, they would spread exactly the same. And, the middle IS differentiated (in 2 channel stereo); it's differentiated by the fact that a signal in the centre position is the ONLY thing in a stereo mix which is identical in both channels. It maybe perceived as less differentiated, not well defined or anchored to the central position IF the stereo system is not setup well. For example, if the left and right speakers are spaced too widely and/or if the listener is not positioned equidistant from the two speakers.
[1] The trick is to fool the hearing by having aspects if spatiality that reminds of natural spatiality.
[2] Speakers and crossfed headphones limit ILD at low frequencies in a way that reminds natural spatiality.
1. Not it's not, you just made that up! With some/most acoustic genres, say a symphony recording, the "trick" is to create an illusion of a believable natural spatiality. But that is most definitely NOT the case with virtually all popular culture music genres. There is no attempt or (artistic) desire to create a "natural spatiality" or an illusion of one, in fact quite the opposite, the natural sound (including the "natural spatiality") is deliberately avoided! The "trick" with these genres is creating something that is deliberately not natural but is subjectively perceived as pleasing. Exactly the same as a modern or impressionist artist is not trying to create an illusion of natural perspective.
2. IF you think that speakers and headphones (with crossfeed) reminds you of "natural spatiality", then you have an issue with your perception! That's rather sad because it means you're not perceiving what was intended and are missing a significant part of the art you have purchased. If I looked at a Picasso cubist painting and it appeared to me as an illusion of a "natural perspective", there'd be something very strange with my perception and it would be rather sad because I'd be missing pretty much the entire point of Picasso's art!
G