U+1F1A1 Squared Seven Point One

The Wikipedia has the following information about this codepoint:

7.1 surround sound is the common name for an eight-channel surround audio system commonly used in home theatre configurations. It adds two additional speakers to the more conventional six-channel (5.1) audio configuration. As with 5.1 surround sound, 7.1 surround sound positional audio uses the standard front left and right, center, and LFE (subwoofer) speaker configuration. However, whereas a 5.1 surround sound system combines both surround and rear channel effects into two channels (commonly configured in home theatre set-ups as two rear surround speakers), a 7.1 surround system splits the surround and rear channel information into four distinct channels, in which sound effects are directed to left and right surround channels (SL and SR), plus two rear surround channels (SBL and SBR).

In a 7.1 surround sound home theatre set-up, the surround speakers are placed to the side of the listener's position and the rear speakers are placed behind the listener. In addition, with the advent of Dolby Pro Logic IIz and DTS Neo:X, 7.1 surround sound can also refer to 7.1 surround sound configurations with the addition of two front height channels (LH and RH) positioned above the front channels or two front wide channels positioned between the front and surround channels.