Rotel RSX-1550 owner manual Dolby Digital, DTS DTS 96/24, DTS Neo6

30 RSX-1550 Surround Sound Receiver

or Pro Logic II decoder extracts each channel and distributes it to the appropriate speakers.

The original Dolby Pro Logic decoder delivered a mono signal with reduced high-frequency content to the surround speakers. A more advanced decoder in the receiver, Dolby Pro Logic II, increases the separation and frequency response of the surround channels for significantly improved performance with Dolby Surround encoded recordings.

Dolby Pro Logic II decoding should be used for any analog recording labeled “Dolby Surround” or any Dolby Digital 2.0 soundtrack. Dolby Pro Logic II does a superb job deriving surround sound from conventional 2-channel stereo recordings, using phase relationships to extract front, right, center, and surround channels. A “music mode” makes Pro Logic II an excellent choice for audio CDs.

Dolby Digital

In 1992, a digital recording system, called Dolby Digital, was first used in the film industry. Dolby Digital is a recording/playback system that uses compression techniques to store large amounts of audio data efficiently, much like the JPEG format stores large photographs in small files on a computer. Because it is capable of performance beyond that of audio CDs and can tailor its output for a wide ranges of system configurations, Dolby Digital is the standard audio format for DVDs and for digital television broadcasting in the United States.

The Dolby Digital system can be used to record up to six discrete audio channels, but can also be used for fewer. For example, a Dolby Digital

2.0soundtrack is a digital 2-channel recording of a matrix encoded Dolby Surround soundtrack. To play a Dolby Digital 2.0 recording, use Dolby Pro Logic II decoding as previously described.

DTS 5.1

DTS 96/24

DTS® (Digital Theater Systems) is an alternative digital format competing with Dolby Digital in both movie theaters and home theater markets. The basic functions of the DTS system are similar to those of Dolby Digital (for example, 5.1 discrete channels), however the technical details of the compression and decoding processes differ somewhat and a DTS decoder is required.

A recent extension of the DTS encoding system is DTS 96/24 and the 6.1-channel version DTS-ES 96/24. These recordings provide the performance of a 96kHz sampling rate while still using the actual 48kHz sampling rate of standard DTS discs.

Like Dolby Digital, DTS can only be used on a digital recording and, therefore, is only available for home use on LaserDiscs, DVDs, or other digital formats. To use the receiver’s DTS decoder, you must connect your DVD player to the receiver’s digital inputs. As with Dolby Digital 5.1, detection and proper decoding of DTS 5.1 signals is automatic.

Note: DVDs with a DTS soundtrack almost always have it configured as an option to the standard matrix Dolby Surround format. To use DTS, you may have to go to the setup menus at the beginning of the DVD and select “DTS 5.1” instead of “Dolby Surround” or “Dolby Digital 5.1”. In addition, many DVD players have the DTS digital bitstream turned off by default and cannot output a DTS soundtrack (even if selected on the disc’s menu) until you activate the player’s DTS output. If you hear no sound the first time you attempt to play a DTS disc, go to the DVD player’s configuration menus and turn on the DTS bitstream. This is a one- time setting and need only be done once.

DTS Neo:6

The most common use of Dolby Digital in newer films, in both the film industry and in home theater, is Dolby Digital 5.1. Instead of encoding multiple surround channels on a two-channel recording, Dolby Digital

5.1records six discrete channels: front left, front center, front right, surround left, surround right, and a Low Frequency Effects (LFE) channel containing ultra-low bass signals intended for a subwoofer. A Dolby Digital decoder extracts the channels from the digital bitstream, converts them to analog signals and routes them to the appropriate amplifiers and speakers. All channels provide full frequency response with total separation between all channels and large dynamic range capability. A Dolby Digital 5.1 soundtrack can provide more impressive surround sound than matrix Dolby Surround.

Decoding of Dolby Digital 5.1 soundtracks is automatic. When the receiver detects a Dolby 5.1 signal on one of its digital inputs, it activates the proper processing. Keep in mind that Dolby Digital is only available from digital sources (a DVD, a LaserDisc, or a Digital TV/Cable/SAT tuner). Also, you must connect the source with a digital cable (coax or optical) to an active digital input on the receiver.

Note: Many DVDs have a Dolby Digital 2.0 matrix soundtrack as the default, which should be decoded with Pro Logic II. The Dolby Digital 5.1 soundtrack may have to be selected as an option from the setup menus at the beginning of the DVD. Look for a Dolby Digital 5.1 selection under “Audio” or “Languages” or “Setup Options” when you insert the disc.

This Rotel receiver features a second type of DTS surround sound decoding: DTS Neo:6. This decoding system is similar to Dolby Pro Logic II and is designed for playback of any 2-channel stereo recording, either matrix-encoded or not. The Neo:6 decoder can be used with any conventional 2-channel source such as a stereo TV or FM broadcast

or a CD. It can also be used as an alternative method of decoding matrix-encoded Dolby Surround recordings or TV broadcasts. Activate the DTS Neo:6 decoding with the DTS Neo:6 button as detailed later in this section. DTS Neo:6 is not used with DTS 5.1 digital sources and the button need not be pressed for those recordings.

Dolby Digital Surround EX

DTS-ES 6.1 and 7.1 Channel Surround

In 1999, the first Dolby Digital soundtrack was released to theaters with an additional center back surround channel, intended to increase the directional effects from behind the audience. This additional surround channel is encoded into the two existing surround channels in Dolby Digital 5.1, using a matrix encoding process similar to that used previously in Dolby Surround. This new extended surround capability is called Dolby Digital Surround EX.

DTS has added a similar capability for recording this extended surround information called DTS-ES®6.1 Matrix. They have also taken it one step further and developed the capability to record this extended surround information as a discrete channel in a system called DTS-ES®6.1 Discrete.

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