What 5.1, 7.1 and 5.1.2 mean, how many speakers you need, and what each one does.
A good home cinema depends on sound as much as picture. A 4K television is little use if the dialogue is muffled and you are straining to follow it. A surround system solves this by spreading the soundtrack across several speakers instead of leaving it all to the television. This guide explains what the numbers mean, how many speakers a surround system needs and what each speaker does. If you would rather talk it through for your own room, see our home theatre design work.
Figures such as 5.1, 7.1 and 5.1.2 count the speakers in a system. Read from left to right, they give the main speakers, then the subwoofers, then the height speakers.
A 5.1 system has five main speakers and one subwoofer. The five are a left and right front pair, a centre speaker, and a left and right surround pair. The subwoofer is a speaker built only for low-frequency sound, and we come to it below. You can see a 5.1 layout in a HDB living room installation.
A 7.1 system has seven main speakers and one subwoofer. The extra two are additional surround speakers, placed at the sides or the rear of the room.
A third number counts the height speakers. These are ceiling speakers, or speakers that fire upwards, and they carry sound that comes from above. So 5.1.2 is a 5.1 system with two height speakers. A 5.2.4 system has five main speakers, two subwoofers and four height speakers. When there is no third number, the system has no height speakers.
It depends on the system you choose, but an entry-level 5.1 set-up is the usual starting point: five speakers and a subwoofer at minimum.
A television sends everything through one source. A surround system sends different parts of the soundtrack to different speakers, so sound moves around you as it does on screen. Here is what each speaker does.
Full-range speakers placed to the left and right of the screen. They handle most of the music and sound effects from whatever is playing.
The centre speaker carries most of the dialogue, so every spoken line stays clear.
Placed to the left and right of the seating, or behind it, surround speakers handle sound that comes from behind, such as footsteps approaching from the back of the room.
The subwoofer reproduces bass and sub-bass. It gives a film its weight: the thud of an impact, the low rumble of an explosion.
Ceiling and other height speakers carry sound that comes from above, such as a helicopter passing overhead or thunder in a storm. They can sit above freestanding speakers, as in a 5.2.4 home theatre with freestanding speakers and ceiling heights, or be built in throughout, as in a 5.2.4 room with in-wall and in-ceiling speakers.
Tell us about the room and how you use it, and we will work out which of these systems suits it.
Tell us about the room and how you use it. We will take it from there.
Tell us a little about your space and how you’d like to listen.
