5.1 – 5 Channels of surround consisting of a left speaker, centre speaker, right speaker and a rear-left and rear-right speaker. The .1 refers to a single subwoofer.

5.2 – The same as a 5.1 system but the .2 now refers to there being 2 subwoofers.

7.2 – 7 Channels of surround consisting of a left speaker, centre speaker, right speaker, a rear-left and right-speaker, and two additional surround speakers typically installed on the side walls. The .2 refers to 2 subwoofers as part of this system.

5.1.2 – 5 Channels of surround consisting of a left speaker, centre speaker, right speaker and a rear-left and rear-right speaker. The .1 still refers to a single subwoofer. Finally the .2 in this instance is referring to “dolby atmos” in ceiling speakers which are installed on the ceiling above your seating position giving you overhead sound. Think of the sound of rain above you, or a helicopter flying over your head.

7.2.4 – This combination is typically used in larger home cinema rooms. It combines all channels we have mentioned above. 7 Channels of surround consisting of a left speaker, centre speaker, right speaker, a rear-left and right-speaker, and two surround speakers typically installed on the side walls. The .2 refers to 2 subwoofers as part of this system, and we now have a total of 4 “dolby atmos” in ceiling speakers providing overhead sound.