The Audyssey DSX Surround Sound Format

Audyssey DSX Logo. Logo provided by Audyssey

In the evolution of Surround Sound, Yamaha's Presence and Dolby's ProLogic IIz were the first audio processing formats to introduce the concept of adding front height channels into a surround sound setup, and DTS briefly provided a similar option with its DTS Neo:X surround sound processing. The goal of these formats was to provide a more immersive surround sound experience.

Dynamic Surround Expansion

In addition to Yamaha, Dolby, and DTS, Audyssey, developers of several automatic speaker setup and room correction systems incorporated into many home theater receivers, also followed with its own twist that was designed to enhance the surround sound experience, Audyssey DSX (which stands for Dynamic Surround Expansion).

Audyssey DSX, in a similar fashion to Yamaha Presence, Dolby ProLogic IIz, and DTS Neo:X, supplies a provision for adding front height channels. However, in a similar fashion as DTS Neo:X, it also provided a surround sound processing option that allows installing either front height speakers and/or wide channel speakers. The wide channel speakers are placed in between the left and right surround speakers and the left and right front speakers. This option is designed to eliminate sound dips that can occur between the front and surround speakers that may occur, especially in a larger room.

Also, depending on the number of amplified channels that may be provided on specific home theater receivers, Audyssey also includes the option of adding both front height and wide channel speakers in the same room setup.

Just like Yamaha Presence and Dolby ProLogic IIz, the ability to use or experience DSX does not require studios to mix soundtracks specifically for the expanded sound field. In other words, the DSX processor looks for cues already present in 5.1 or 7.1 channel soundtracks and directs them to added front height and/or wide channels, enabling a more enveloping "3D" sound listening environment.

Channel and Speaker Configurations

In order to experience the maximum benefit of Audyssey DSX, you need a 9.1 channel home theater receiver that is Audyssey DSX-enabled. However, DSX is adaptable for use in 7.1 channel configurations (you have to choose between using front height or wide speakers).

In a full 9.1 channel DSX setup, the speakers are arranged as follows: Front Left, Front Left Height, Front Center, Front Right, Front Right Height, Wide Left, Wide Right, Surround Left and Surround Right. The Wide Left and Wide Right speakers are placed on sides between the front and surround speakers. The .1 channel, of course, is reserved for the Subwoofer(s).

If you are limited to a 7.1 channel setup, you have two options: You can eliminate either the front height or wide speakers. Audyssey recommends that if you have to make this choice, adding wide speakers should be a higher priority over adding the front height speakers.

This means that for a 7.1 channel setup if you opt for height, the speaker layout would be Front Left, Front Height, Front Center, Front Right, Front Height, Surround Left and Right, and Subwoofer.

However, if you opt for the wide option instead, your speaker setup would consist of Front Left, Front Center, Front Right, Left and Right Wide, and Surround Left and Right and Subwoofer

A layout with the wide speaker setup option allows for the expansion of the surround sound field that fills in the gaps between the surround and front speakers, as well as adding a larger front soundstage with the addition of height channels placed above the front left and right front speakers. If you opt for height speaker option, the sound from the height speakers projects toward the listening position, giving the sensation of selected sounds coming from overhead.

Audyssey DSX and DSX 2

Home Theater receivers that are equipped with Audyssey DSX have the ability to upmix 5.1 or 7.1 channel content, while DSX 2 adds the ability to upmix 2.0, 5.1, or 7.1 channel content into the intended expanded surround sound environment.

The Bottom Line

Although there are some home theater receivers that come equipped with the Audyssey DSX or DSX2 surround sound processing formats, with the introduction of the Dolby Atmos, DTS:X, and Auro3D Audio immersive surround sound formats, since 2015, home theater receiver makers have moved away from the Dolby ProLogic IIz and Audyssey DSX/DSX2 options. However, Yamaha still includes its Presence surround sound processing option on some of its home theater receivers.

However, if you have a home theater receiver, or happen to buy one, that has either DSX or DSX2 as an option, it can still be used, as it does not require specific encoding on the source end, and can definitely expand your surround sound listening experience over standard 5.1 or 7.1. Take the time to experiment and see if you like what you hear.