Q. What Are the Differences Between Dolby Digital, Dolby TrueHD, DTS and DTS-HD?

Bryant Moore of Moore Audio Designs breaks down these competing multi-channel audio formats.

Mar. 13, 2008 — by Bryant Moore

Q. What are the differences between Dolby Digital, DTS and the newly introduced Dolby TrueHD and DTS-HD and how do I upgrade to these new surround sound formats? - Juan, Roanoke, VA

A. Dolby Digital and DTS are two different (and competing) multi-channel audio formats. Dolby Digital is developed by Dolby Laboratories, Inc. and DTS by Digital Theater Systems, Inc. Both are capable of encoding 5 full channels and one low frequency effects (LFE) channel. The five channels are Front Left, Center, Front Right, Left Rear and Right Rear. The EX (with Dolby) and ES (with DTS) adds two rear channels (6 and 7). One of the fundamental differences between Dolby Digital and DTS is that DTS encode their digital audio soundtracks at a higher bit-rate than does Dolby. In theory this should make the soundtrack on a DTS-encoded DVD sound better than an equivalent Dolby Digital soundtrack, but in practice, this is not always the case. 

The new Dolby TrueHD and DTS-HD formats provide the digital audio signal at significantly higher bit-rates than that encoded on traditional DVDs. They are also the first real “lossless” audio technologies developed especially for new high-definition disk formats like Blu-ray and HD-DVD. The promise of these two new high-resolution digital audio formats is that they can deliver a true bit-for-bit recreation of the original studio recording. They both offer 8 discreet channels (7.1) of audio.

You can take advantage of these two new high resolution audio formats by upgrading to a Blu-ray Disc or HD-DVD player with Dolby TrueHD and DTS-HD Digital Outputs and a new AV Receiver with Dolby TrueHD and DTS-HD decoding built-in. Simply connect the disk player to the receiver using an HDMI cable. If you aren’t planning on purchasing a new AV receiver with the new format decoding built in, you can connect the Blu-ray Disc or HD-DVD player to the older Dolby Digital/DTS receiver by using 6-8 analog audio cables, depending on how many output channels (speakers) you are using. This is called a “line-level” connection.

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