Dolby Atmos speaker placement (5.1.2, 5.1.4 and 7.1.4)

What the numbers mean

Atmos layouts are written as three numbers: ear-level speakers . subwoofers . height speakers. A 5.1.2 system is a normal 5.1 plus two height speakers; 7.1.4 is 7.1 plus four. The ear-level part is placed exactly as in 5.1 or 7.1. The heights add sound from above: rain, flyovers, the room around a scene.

In-ceiling height speakers

Dolby specifies height speakers by their elevation angle: how far above your ears they sit, measured from straight ahead.

To turn an angle into a ceiling position: take the height of the ceiling above your ears (ceiling height minus about 3.9 ft). At 45°, the speaker sits that same distance in front of or behind your head. In a room with an 8.5-ft ceiling that’s about 4.6 ft forward and 4.6 ft back. Dolby’s guidelines also note that height speakers work best mounted at two to three times the height of the ear-level speakers.

Up-firing (Atmos-enabled) speakers

If you can’t put speakers in the ceiling, up-firing modules and soundbars bounce sound off it instead. Dolby’s rules for them:

• On top of the front left and right speakers (and ideally the rear or side surrounds for a second pair), or within about 3 ft (0.9 m) of them.
• At or slightly above ear height, no higher than half the wall height.
• At least 3 ft (0.9 m) from listeners, ideally 5 ft (1.5 m), so you hear the reflection rather than the speaker.
• A flat, acoustically reflective ceiling 7.5 to 14 ft (2.3–4.3 m) high, ideally under 12 ft. Angled, vaulted or acoustic-tile ceilings scatter or absorb the reflection.

The same ceiling rules apply to Atmos soundbars. Sonos and Bose both say not to put an Atmos bar inside a cabinet or under a shelf, where the up-firing drivers are blocked.

Which Atmos layout for your room?

• Living room, sofa against the back wall: 5.1.2. Two top-middle speakers slightly in front of the sofa add height without needing space behind you.
• Living room with space behind the seats: 5.1.4 or 7.1.4, if the ceiling allows four speakers.
• Rented home, can’t cut the ceiling: an Atmos soundbar or up-firing modules on the front speakers, if the ceiling is flat and hard.
• Dedicated theater: 7.1.4 or more, in-ceiling.

Whatever the layout, keep left–right pairs symmetrical, aim speakers at the main seat where the mounting allows, and run room calibration afterwards.