DTS-HD Master Audio: What You Need To Know

Taking surround sound up a notch

DTS-HD Master Audio Logo
Image provided by DTS

DTS-HD Master Audio is a high definition digital surround sound format developed by DTS for home theater use.

The format supports up to 8 channels of surround sound with increased dynamic range, wider frequency response, and higher sampling rate than other DTS surround formats. Its closest competitor is Dolby TrueHD.

Similar to Dolby TrueHD, DTS-HD Master Audio is primarily used in the Blu-ray Disc and Ultra HD Blu-ray formats. It was also used in the discontinued HD-DVD format.

How to Access DTS-HD Master Audio

A DTS-HD Master Audio signal can be transferred from a compatible source (such as Blu-ray/Ultra HD Blu-ray) in two ways.

  1. Through a DTS-HD Master Audio encoded bitstream, via HDMI (ver 1.3 or later) to a home theater receiver with a DTS-HD Master Audio decoder. The receiver decodes the signal and passes it through its amplifiers to the speakers.
  2. Through a Blu-ray Disc/Ultra HD Blu-ray player to decode a DTS-HD Master Audio signal internally (if the player has the option). The decoded signal is passed to a home theater receiver as a PCM signal via HDMI, or, via a set of 5.1/7.1 channel analog audio connections. The receiver doesn't need to perform additional decoding or processing; It passes the decoded audio signal to the amplifiers and speakers. Not all Blu-ray Disc players provide the same DTS-HD Master Audio internal decoding options; some only provide two-channel decoding, rather than 5.1 or 7.1 channel decoding.

The internal decoding to analog audio option requires a Blu-ray/Ultra HD Blu-ray player with a set of 5.1/7.1 channel analog audio outputs. The home theater receiver has to have a set of corresponding 5.1/7.1 channel analog audio inputs. Both options are now rare.

Unlike the DTS Digital Surround format, DTS-HD Master Audio (either un-decoded or decoded) can't be transferred by Digital Optical or Digital Coaxial audio connections. There is too much information, even in compressed form, for those connection options to pass DTS-HD Master Audio signals.

Digging A Little Deeper

With DTS-HD Master audio encoding, the soundtrack is bit-for-bit identical to the original uncompressed recording. As a result, DTS-HD Master Audio is classified as a "Lossless" audio format (a claim also made by Dolby Labs for Dolby TrueHD).

The sampling frequency for DTS-HD Master Audio is 96kHz at 24-bit depth. The format supports transfer rates on Blu-ray of up 24.5 Mbps, and 18 Mbps for HD-DVD (for those that still have HD-DVD discs and players).

Dolby TrueHD supports up to an 18 Mbps transfer rate on Blu-ray or HD-DVD.

Although DTS-HD Master Audio can provide up to 8 channels of audio (7 full channels and 1 subwoofer channel), it can also provide a 5.1-channel or 2-channel format (although the 2-channel option is rarely used).

When used with Blu-ray Disc content, either a DTS-HD Master Audio soundtrack or a Dolby TrueHD/Atmos soundtrack may be included, but rarely will you find both options on the same disc.

DTS-HD Master Audio is backward compatible. That means even if you have a Blu-ray or Ultra HD Blu-ray Disc encoded with a DTS-HD Master Audio soundtrack, you can still access a standard DTS Digital Surround soundtrack if your player or home theater receiver is not DTS-HD Master Audio compatible. Also, for those home theater receivers that do not have HDMI, you can access standard DTS digital surround via the digital optical/coaxial connections.

The DTS-HD High-Resolution Audio Alternative

A variation of DTS-HD Master Audio, DTS-HD High-Resolution Audio (DTS-HD HR) is sometimes used in place of DTS-HD Master Audio. It has a more limited bit-rate (3 to 6 Mbps), but the same bit depth and sampling rate as DTS-HD Master Audio. It can be used for Blu-ray or Ultra HD Blu-ray Disc applications when there may not be enough space for lossless DTS-HD Master audio due to the inclusion of added video or soundtrack options included on a disc.

Just as DTS-HD Master Audio is built on top of the DTS core, so is DTS-HD HR, making it backward compatible with other DTS surround sound formats should your home theater receiver not have the ability to decode the DTS-HD High-Resolution format.

DTS-HD HR occupies a similar position as Dolby Digital Plus does in relation to Dolby Digital and Dolby TrueHD.

The Bottom Line

Can you hear the difference between DTS-HD Master Audio and Dolby TrueHD? Maybe, but you need a really good ear to tell. Also, the capabilities of your home theater receiver, speakers, and even your room acoustics will come into play for the final listening result.

To take things further, DTS also offers the DTS:X format, which adds more immersion than DTS-HD Master Audio. The format can be accessed from properly-encoded Blu-ray/Ultra HD Blu-ray Discs and a DTS:X-enabled home theater receiver.