Audiovisual receivers buying guide

AV receivers sell the idea of turning your living room into a cinema. How much should you spend?
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05.Jargon buster

AIR Studios

Originally set up by George Martin, of Beatles fame, and is now a recording studio which provides certification to a set of quality standards for some audio products. Similar to THX (see below) in that regard.

Audio delay

Allows for the difference in video and sound processing in some home theatre set ups, which is responsible for a lack of 'lip sync'. It's called 'A/V SYNC' on our SONY examples, but other manufacturers may use different names.

Auto set up and calibration

Usually involves attaching a supplied microphone and placing it in the normal listening position, then running an automated set up process. This uses a variety of sounds to determine the location of each speaker and the characteristics of the room to give a balanced sound at the listening position. SONY calls its system Digital Cinema Auto Calibration (DCAC). Other common names for this sort of system are Audyssey and MCACC.

DAB, or digital audio broadcast

More commonly known as digital radio. Some AV receivers have a built-in tuner. Digital radio broadcasts are currently available in capitol cities only, but this will change over time.


Digital to analogue converter which takes the digital information from a CD or DVD and converts it into electronic pulses that can be amplified to produce sound. (Burr Brown is a brand name often associated with DACs.)


A brand name for technologies that are used to manage sound production. Some of Dolby's products are:

  • Digital / Plus is an upgrade of the Dolby codec (a method of making data smaller for storage or transmission, and then unpacking it again for playback) to allow for more channels and greater efficiency.
  • Digital Surround EX includes encoding for an extra centre surround channel which can be mixed into the rear speakers in a 6.1 or 7.1 system.
  • Pro Logic II / IIx takes stereo or 5.1-channel audio and makes it possible to play back via a 6.1 or 7.1 channel system.
  • TrueHD is designed with Blu-ray discs in mind. It's a lossless (no data is lost in the process) coding technology and can support more than eight audio channels, even though Blu-ray supports only eight at present.


Also a brand name for sound encoding technologies. Some common products are:

  • Digital Surround is an encoding often found on standard DVDs. It supports both two and 5.1 channels.
  • DTS-ES is similar to Digital Surround, but supports 6.1 channels.
  • DTS-HD Master Audio is a lossless encoding designed for use on Blu-ray (and formerly HD-DVD) discs. Like Dolby TrueHD, it can support up to eight channels.
  • DTS Neo:6 enables stereo audio to be played back via a 6.1 channel system.


High-Definition Multimedia Interface is a protocol (set of instructions). It's also a digital connection which can carry video, sound and device control information.


A brand name for a video processing chip often associated with 'up-scaling'.


Pulse code modulation, is a method of encoding sound waves into a digital form. Higher bit rates generally mean better quality.


Root mean square and applies to the power figures for amplifiers. It's considered a better means of comparison than 'peak' or 'dynamic' power because it is a better measure of the power an amp can deliver over a reasonable length of time rather than in very short bursts.


A trade name for a set of quality standards for hi-fi equipment and cinemas.

Toroidal Power Transformers

Smaller, more efficient and may have less interference problems than some other types of transformer.

Up scaling

Where a video signal from a DVD, which has 576 lines of data for each frame on the screen, has extra lines added to appear on a high-definition screen with typically 720 or 1080 lines.


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