A fairly well set-up 5.1 / 7.1 with surrounds located on side walls rear wall all at even height so one sound appears to move one to the other. LCR should always be matched and placed at the same height about middle height of the room that vary from room to room.
Reason for the stage channels to be high up is so that the sound reaches the front and back row seating. I seen lot of home dedicated rooms where speakers are positioned on the floor and no way the sound will reach the back row as the seats in front and bodies will also absorb some of the sound.
Been watching some AIR FORCE ONE (1996) region 2 DVD, and wow this film still has thrilling Dolby mix. It would be wild to listen too to it with re-mix, "Dolby Atmos-Plus", Re-mix of older films will happen in Atmos.
With below stereo surround channel and a 9 to 15 channel array that would allow for height and below sound to match the on-screen visuals.
Upper and lower corner surrounds for directional and defused surrounds where off-screen sounds can follow, would create a better sense of involvement with advanced cinema listener goers.
Also half pans can happen between upper surround corners to the middle surround arrays and middle arrays to below corner floor and back wall arrays.
The current 4 extra or up 34 for home or 64 for cinema isn't enough.
Difficulty with home would be where some surrounds are placed due to door to the room. In a cinema the door/s are often placed in large premiere cinemas leading to the middle of the auditorium. Some multiplexes ether have single door leading to one side the auditorium at the back with narrow aisle leading down the side with rows of stadium seating in the middle of the cinema.
In the home locating below corner surrounds would be tricky to making sure one doesn't trip over them. or could be fitted in flush into the wall lower to floor so any off-screen sounds that pan off screen moving at downwards angle should sound in those positions with a "pan-though".
Somehow I don't see Dolby updating Atmos any sooner. 70mm had few make-overs during the mid '70's and soon one format was settled on that became to be known as 5.1.
A scene in Air Force One that I looked at over and over looking at where it would be logical to place 15 screen sound and off screen sounds with the re-fueling plane going up in ball of flames.
Outside scene would have the jet engines to left off screen in the distance with rushing air being pushed all around the front of the nose of 747.
The re-fueling line would be panning across the middle stage channels right centre across to centre and upwards to height screen channels upper-left-centre to upper-left, would make sense in a now "Atmos world" But the standardize Atmos needs to updated.
There should also be rushing air all over the stage channels and surrounds overhead corner surrounds above and below back surrounds above middle and corner floor areas and below surrounds, as the both planes are miles up in the air.
Interior scene seen from the pilot in the cockpit of the re-fueling line rubbing aganst the window moving upwards, should sound from centre middle with sprays of fuel leaking across the wider over the rest of the stage channels middle below above as its close-up shot for brief few seconds.
Terrorist leader and pilot looking upwards as the re-fueling line bumps up and down on the outside above, on the cockpit should sound on the upper stage channels upper-left and upper-right with smaller sound down on middle stage channels left and right and lesser on below-left below-right at different sound frequency to create some sort of alarming moment.
Re-=fueling line sparks on the topside of the 747 and ignites the leaking fuel starts to trail up the fuel line to the re-fueling plane. Sound of air rushing around should be on stage channels and equally so on the surrounds everywhere as the plane is miles up in the air!
Fuel leaking and fire starting should sound on middle stage left-centre to left.
Fire grows larger as it starts to climb up the fuel line. should sound on middle stage channels left and left-centre.
Again rushing air all around should be on all channels to heighten realism.
Interior of cockpit the scene seen from this angle should have the fuel line and the fire sounding from above surround channels as the re-fueling plane is located above the the 747 in front.
Air force one 747, starts to pull away from the burning fuel line. The 747 drops down over to stage left. Complex scene I see here.
The sound of engines of the 747 are at the angle would be located off-screen above so engines should sound on the upper stage channels and as the plane drops off screen to left the sound should track with the engines coming into view sound on the middle stage channels to below.
The burning fuel line should sound on the upper-right-centre to right with the re-fueling plane engines sound somewhere on the upper corner surrounds and party somewhere across the height channels as the wing-span don't forget would be in the same positioning as the 747 only its above it.
747 Air force one banks downwards to escape the exploding re-fueling plane.
Air should be rushing all around and fuel line on fire sounding on upper centre, The 747 engines panned to below-left, the other engine on-screen should be sounding on the middle-right-centre.
Fire rages upwards to the ill-fated re-fueling plane and explodes. The air should be rushing around on all channels and the fire sound would be a bit louder as its close-up as its flaming away on below left to below left-centre to middle left and left-centre to above left and above left-centre.
Fire hits the aft end of the plane and erupts into a huge fireball.
Engines sounding should be on middle stage to below stage channel as the air craft tries to stabilize.
KABOOM! The aft end explodes should sound on below and middle stage left, left-centre. Air rushing all around at same time,
Explosion moves up and though the air aircraft completely engulfing it.
Sound of KABOOM should be mostly moving across below middle and upper stage channels.
Air force pilot sees the exploding plane. Dialogue would be best on middle left stage channel 100% with no half pan to left or centre, it would sound much cooler than "common centre channel" as the pilot in this shot isn't positioned within the middle of the scope frame.
The explosion should and would sound better alone the side wall surround (with pan-though) would best near to the corner middle surround at back and partly on the rear middle back wall surround, from looking at the angle of the scene. The plane by now has already lost some altitude due to the damage and is fulling out of the sky.
Air sound should be rushing around all around and the F-15 engines should be off screen to below left and middle left.
Air rushing all around on all channels and F-15 engines should sound on below left and below left-centre with small shifts in the sound.
The other F-15 should sound on the middle right-centre to right, again with small panning shifts in the sound as both plans are moving about.
Explosion would be a bit distant and located in the middle-centre channel.
Re-fueling plane burning above on middle stage channels and gradually moves across on-screen. 747 engines would be located on the below stage channels left-centre right-centre and gradually move into the shot should widen outwards.
Here in this should the engines are seen and one engine on below stage left-centre the others on middle stage left-centre right.
Explosion of the plane above on middle below stage left-centre centre, middle and partly upper stage channels as its very dynamic scene.
Air force one 747, should pan off screen with the engines located on overhead surrounds with windy air rushing around on all channels.
The president floating around on the parachute ramp should be sounding on middle stage centre to left-centre, with burning fireball of flames and fulling airplane in the background shot.
Wider shot should have the sound of the fireball burning in the upper middle and partly below stage channels with air rushing around outside and the inside of plane on surrounds should carry some sort of background noise?
Re-fueling plane falls downwards should sound on upper middle and below stage channels lett, left-centre with small traces of sound distant on the other stage channels and the windy air rushing around as this is miles up in the sky.