High Definition formats are designed to deliver better quality picture and sound. You have probably noticed that many devices now support variety of new video resolutions and audio decoding standards. In this section of our website we will try to give you a simple explanation of the main differences between the old and new technology. HIGH DEFINITION AUDIO Before we can look closer at the new high definition audio formats we need to understand the basics of multi-channel audio processing and hardware connectivity. Below you will find diagrams for the most common multi-channel speaker configurations. 5.1 – front speakers [L+R] + center speaker [C] + side speakers [Ls+Rs] . low frequency speaker [LFE] 7.1 – front speakers [L+R] + center speaker [C] + side speakers [Ls+Rs] + back speakers [Lb+Rb] . low frequency speaker [LFE] To drive these speakers you will need amplifiers (one channel per each speaker) and a sound processor (device that decodes the sound and drives the amplifiers). It is very common for sound processors and amplifiers to be integrated together in a single device (receivers). This solution reduces the cost, saves space and it’s easier to install, however when audio decoding standards change you may need to purchase another receiver. If your receiver’s amplifier was designed to accept direct analog signals for each channel you may only need to purchase a new decoder that supports high definition audio standards or a player that has a build in decoder. There are three ways of connecting your high definition player to your sound system: ANALOG [multi channel analog signals, doesn’t need processing or digital to analog conversion] SPDIF (Optical or Coaxial) [digital encoded signal, processing and digital to analog conversion required] HDMI 1.3 [digital encoded or PCM signal, processing and/or digital to analog conversion required]   ANALOG   SPDIF   HDMI Audio formats compared: Format Max channels Connection Max Bitrate Compression Supported by all devices DD (Dolby Digital) 5.1 ANALOG SPDIF HDMI 640 kb/s Format familiar from DVD, sometimes know as AC-3. Considered equal to DD+ at the same bitrate. Yes DTS 5.1 ANALOG SPDIF HDMI 1.5 Mb/s Format familiar from DVD created by Digital Theater Systems Yes DD+ 7.1 ANALOG HDMI 1.7 Mb/s Encoded as extension to a standard Dolby Digital track, sometimes known as E-AC-3, DD+ offers higher bit rates and better compression Many players read the 640 kb/s DD core discarding the extension DTS-HD 7.1 ANALOG HDMI 6 Mb/s Encoded as extension to a standard DTS track, offers higher bit rates and better compression Many players read the 1.5 Mb/s DTS core discarding the extension PCM 7.1 ANALOG HDMI 35 Mb/s Exact replication of the studio master, encoded on disc without compression, up to 24 bit resolution Yes TrueHD 7.1 ANALOG HDMI 18 Mb/s Lossless compression codec, takes up less space than PCM track, up to 24 bit resolution No DTS-HD Master 7.1 ANALOG HDMI 24.5 Mb/s Encoded as extension to a DTS track, offers lossless compression at up to 24 bit resolution Many players read the 1.5 Mb/s DTS core discarding the extension If you have already purchased a high-quality 5.1 sound system and your receiver can accept analog inputs for all channels, you may find that purchasing an external decoder or player capable of decoding the new audio formats may be the most cost effective solution. If you are shopping for a brand new audio equipment make sure that your new receiver supports all of the new audio standards. If your budged is higher than average you should consider purchasing a seven channel amplifier, a subwoofer amplifier (or an active subwoofer) and a decoder to future proof your entertainment system. Please note that you will only be able to appreciate the lossless audio formats on a high quality audio equipment. It would be a considerable waste of money trying to upgrade most of the inexpensive compact systems.