- What does AC-3 mean?
- AC-3 is a perceptual digital audio coding technique that reduces the amount of data required to produce sound at high quality. Perceptual digital audio coding takes advantage of the fact that the human ear is emitting a certain amount of noise perceived as noisy.
- Reducing this noise, removing it or masking it significantly reduces the amount of data that must be provided.
- Dolby Laboratories has developed two detection encoding systems, AC-1 and AC-2. Based on Dolby’s previous two encoding systems, the AC-3 was the first encoding system specially designed for multi-channel digital audio. AC-3 is an audio format for digital television (DTV), digital versatile discs (DVD), high definition television (HDTV) and digital cable and satellite broadcasts.
- AC-3 is in 5.1 format, which means that the front left, front right, center, surround left and surround right provide five full bandwidth channels.
- There is a low frequency effect (LFE) channel for the special effects in the movies and the sound required for the action sequences.
- The LFE channel is one-tenth of the bandwidth of the other channels and is sometimes mistakenly called subwoofer channel. The AC-3 is also compatible with devices that do not support 5.1 format.