When talking about home theater systems, the following terms are often used: Dolby Digital 5.1, Dolby Digital EX (6.1), Dolby TrueHD 5.1 or 7.1, DTS 5.1, DTS-ES (6.1), DTS-HD Master Audio 5.1 or 7.1, or PCM 5.1 or 7.1. But what do they mean?
Surround Sound | Everything You Need to Know (in 5 Minutes!)
Dolby and DTS are brands that license their audio encoding technologies to various electronics manufacturers. The number after the brand name refers to the type of sound system for which a device or media is formatted. These systems include surround sound, home theater receivers, DVD/Blu-ray players and discs, and other components.
The first number in "Dolby 5.1" for example refers to the number of channels a home theater receiver can provide. It can also refer to the number of channels present in a movie, TV, or video soundtrack. It is more common for systems to support 5, 6, or 7 channels, but some systems are available with as many as 9 or 11 channels.
The second number in the specification refers to a separate channel that reproduces only very low frequencies. This extra channel is a Low-Frequency Effects (LFE) channel. LFE is essential for film soundtracks, because it provides deep, booming tones, but it is also crucial for high-fidelity music.
