Add a centre channel first, a subwoofer second, rear speakers third, and height channels last — that is the order in which each one changes what you hear.
Why the centre comes first
Most of a film’s dialogue is mixed to the centre channel. A stereo pair reproduces it as a phantom image between the speakers, which works when you sit exactly in the middle and degrades as you move. A physical centre speaker anchors voices to the screen for everyone on the sofa.
Why the subwoofer comes second
It relieves the other speakers of the work they are worst at, which makes the whole system sound cleaner at volume, not just deeper. It is also the one speaker whose position in the room matters more than its price.
Why the rears come third
Effects and ambience, rather than the body of the soundtrack. They are worth having and they are also the channels most often placed badly — slightly behind and above the seats is the target.
Why height comes last
Because it asks the most of the room. Up-firing modules need a flat, hard, horizontal ceiling; on a sloped, beamed or absorbent ceiling they produce very little. In that room, the money goes further in a better centre speaker.
Questions people actually ask
What does the third number in "5.1.2" mean?
Height channels. The first number is the speakers around you, the second is subwoofers, and the third is speakers aimed at or reflecting off the ceiling. A "5.1" system marked Dolby Atmos decodes the format without having dedicated height speakers.
Is 7.1 worth it over 5.1?
In a large room where the seating is well forward of the back wall, yes: the extra pair fills the space behind. In a small room where the sofa is against the wall, the rear speakers of a 5.1 are already behind you and the additional pair has nowhere useful to go.
Last reviewed 4 September 2026