I've just had my 2nd listen, this time in 5.1 and I'm getting vocals in all 5 speakers, I wouldn't say vocals where mixed low though. Yesterday I listened in Atmos and it seemed (though I didn't put my ear to the speakers) that vocals where from the surrounds (not rears) and I didn't like it, which is why I thought I'd try 5.1 today, still not keen on the vocal mix.
I'm guessing that because Bruce is in the middle with the camera moving round him that his vocal is coming from the middle of the room.
I have had the first full listening today.
I like very much that the Bruce vocals is not in front as usual. Yes, it comes from the two (side) surrounds. If your layout is with surrounds at the sides (90º), as mine, you may hear in the sweet spot his voice either “into your head” or coming from the ceiling above, because of some binaural effect. But the vocals do not come from the top speakers in the main film.
Fortunately, the four music videos are mixed in Atmos, and there the main vocals is coming also from the top speakers, enlarging the sound bubble sensation.
It is also good that the backing vocals (mainly from Jon Sykes, bass) are coming from the left surround, making a good separation from the Bruce main vocals.
For me, it is very conservative when the vocals are coming only from the front, and worst only from the Central speaker. Many of us appreciate discrete instruments coming from the surrounds (sides or rears), even if the musician playing an (electric) instrument is located visually in the front. Why not also the main vocals, that are also electric (via the micro/amp)? That allows a more successful sound bubble, and the voice is not muffled by the other instruments as in some other surround mixes.
For people that prefer the vocals coming from the front, there is the alternative of the 5.1 mix (I think it is mixed this way), or even the Stereo, that could be both upmixed with the AVR. So many choices to play and compare.
This Bruce Atmos mix is not as aggressive as Yello-Point with ping-pong sounds, but I find the sound very clear and discrete, to perceive each instrument, and with a good enough sound bubble immersion.
Special mention to Gavin Harrison and his drum set, that looks so clean and brand-new, with the very clean Batter Heads. Just see his long “would like to thank” list in the credits. With the PIP option of Gavin drum-cam, you may no longer have the need of looking for Gavin Youtube videos to see his performance. But sometimes the drum-cam video montage is not as good as I would like, and some details are lost like, for example, when a quick two-feet bass drum occurs and the cameraman loses most of that play.