What is 7.1 Audio?

• Digital surround sound can make a regular DVD-watching experience more akin to seeing the movie in a theater. With pounding bass and a spatial soundtrack, the audio pulls you into the picture and places you right in the middle of the action. One of the newest variations of home theater systems are the ones that offer 7.1 surround sound capabilities. Whereas digital 5.1 surround delivers sound from the front, middle and rear, 7.1 digital surround fully surrounds you with audio from the front, middle, rear and sides.
  
  

The 7.1 Speaker Breakdown

• Here is how a 7.1 speaker system is set up: two speakers in the front deliver left and right spatial sound. One speaker in the middle front delivers the dialogue. Two speakers, one on each side, offers spatial sound coming from the sides. Two speakers in the rear offer spatial sound coming from behind the viewer. One subwoofer offers heart-pounding bass to complete the experience.
  
  The seven primary speakers make up the 7 with the .1 being assigned to LFE, or subwoofer, hence the 7.1 configuration.
  
  

How 7.1 Audio Works

• Standard DVDs offer maximum data rates of 1.5 Mbps. Today's HD DVDs and Blu-Ray discs can handle up to 6 Mbps, depending on the format. This increase in capacity means that audio can now be stored on these discs in a "lossless" format, meaning that the audio does not get compressed. As such, it allows for 7.1 discrete channels with a sampling frequency of 96 kHz and 24-bits of resolution.
  
  When you play an HD DVD or a Blu-Ray disc in a player with an internal DTS decoder, the audio signal is sent into the disc player's DTS decoder and mixer. From the mixer, it travels through the HDMI cable into your DTS-ready receiver. There, it is collected in the DSP post processor. From there, the audio signal is sent to the DAC (digital to analog converter).
  
  The signal is then sent to the amplifier, which separates the signal into 7.1 discrete channels and outputs the correct signal to the proper speaker.
  
  

Compatible Audio Formats

• If you wish to take advantage of 7.1 audio, then you will want to look for equipment and media that features Dolby Digital Plus, DTS-HD, Blu-Ray or Dolby TrueHD compatability.