Sunday, December 23, 2007

Home Cinema Sound

We hear a lot about 5.1 surround sound on DVDs. Basically, all one-box home cinema systems with five speakers and a subwoofer can handle 5.1 soundtracks. 5.1 refers to a multichannel soundtrack that is split into five discrete channels of digital sound information.

Each of the five individual channels provide sound to the front left, front right, centre, surround left and surround right speakers. A sixth channel is reserved for the subwoofer, and is referred to as the .1 in a 5.1 soundtrack.

Prerecorded DVDs contain a variety of digital soundtracks. The most popular soundtrack format is Dolby Digital 5.1. It’s found on most DVD blockbuster movies, and all home cinema systems can handle Dolby Digital 5.1 surround sound. DTS 5.1 is the direct rival to Dolby Digital 5.1, and is found on an increasing number of DVD soundtracks. DTS is generally considered to be of superior sound quality, but not all systems are compatible with it so it is worth checking before you buy.

Newer formats called Dolby Digital EX and DTS ES are emerging with a 6.1 multichannel soundtrack. These utilise a rear-centre channel for more effective wraparound effects, and will appeal to anyone who owns a home cinema system with six surround speakers.

Just around the corner are high definition formats called Dolby Digital Plus and Dolby TrueHD. Dolby Digital Plus was designed as a bridge between existing hardware and high definition formats, including HD DVD, Blu-Ray and HDTV broadcasting. The format is based on Dolby Digital but enjoys more efficient coding. It works with multichannel audio programs of up to 7.1 channels. Dolby TrueHD is designed for HD DVD and Blu-Ray and delivers sound that is identical to the studio master.

Dolby Digital or DTS?

Consumers probably don't care if a DVD movie release uses Dolby Digital or DTS for surround sound because, by the time the product reaches them, the decision to encode the audio with Dolby or DTS has been made by the studio.

Most home cinema playback systems support both Dolby Digital and DTS decoding and many titles are issued with Dolby Digital and DTS encoded tracks on the same DVD.

Both systems provide high-quality 5.1 digital audio that can be played through the same amplifiers and loudspeakers. On dual standard titles, the consumer can select the Dolby Digital or the DTS soundtrack from the audio submenu.

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