HDTV doesn’t just mean great picture, it also means great sound. Dolby Digital can deliver immersive 5.1 channel surround sound to perfectly complement the improved visual experience offered by HDTV. A Dolby Digital 5.1 broadcast can captivate you in a way which stereo cannot, for films delivering a true cinematic experience, for sport placing you with your team right ensuring you don’t miss the action. In fact for any content Dolby Digital delivers the experience the audience demand.
Dolby Digital is the format of choice for film with over 40,000 cinema screens equipped and standard for DVD worldwide entertaining millions of people every year.
Dolby Digital is the format to deliver surround sound for films, sport and drama but its flexibility also allows for mono and stereo broadcasts with seamless switching between mono, stereo and surround its ideal for all direct to home broadcasting. Increasing the flexibility yet further is the ability of Dolby Digital Decoders to take 5.1 sound tracks and create stereo, a process called downmixing, for situations where a 5.1 system is not available. It’s even possible to downmix right down to mono for a portable TV.
Dolby Digital is also easy to use both for the broadcaster and for the end user in the home. In the home it’s as simple as making one digital connection from the set top box to a surround system. Even surround systems available now are easy to set up usually having intuitive colour coding for connections and simple on screen menus to guide you. Speaker positioning is quite straightforward and usually takes only a few minutes, often smaller satellite speakers are used which are even easier to place.
Set-top boxes often also feature a stereo analogue output feature for cases when a surround system is not in use. These outputs can deliver a downmix of the Dolby Digital stream avoiding the need for the broadcaster to transmit an addition stereo track using valuable bandwidth.
Discrete means that the sound information contained in each of the six available channels is distinct and independent from the others. These six channels are described as a "5.1-channel" system, because there are five full-bandwidth channels (left, centre and right at the front together with left and right at the Back) with 3 Hz to 20 kHz frequency range plus one "low frequency effects" (LFE) subwoofer channel devoted to frequencies from 3 to 120 Hz.