Arcam AVR250 manual Surround modes, Digital multi-channel sources

Surround modes

Introduction

Your AVR250 processor provides all the key decoding and processing modes for analogue and digital signals.

Modes for Digital sources

Digital recordings are usually encoded to include information about their format type. The AVR250 detects automatically the relevant format in a digital signal, such as Dolby Digital or DTS, and switches in the appropriate decoding.

Modes For Analogue sources

Analogue recordings do not contain information about their encoding formats, so the desired decoding mode – such as Dolby Pro Logic – needs to be selected manually.

Mode Memory

The AVR250 has a comprehensive memory that allows it to store different settings for each source button. The text below applies to all inputs except ‘DVD-A’.

Dolby Digital or DTS audio data (sometimes collectively referred to as ‘bitstream’ sources) can be output in three mix modes, selected using the MODE button:

nSurround (e.g., five main channels plus a subwoofer for a 5.1 source)

nStereo Downmix

nMono Downmix

The AVR250 will remember which mix mode was last used with a bitstream source. See ‘Multi-channel Source Modes’ for more information.

Two-channel audio, regardless of whether it is analogue or digital also can be output in three mix modes, selected using the MODE button:

nSurround (e.g., Dolby Pro Logic IIx Movie, Neo:6 Music, etc.)

nStereo (with effects applied for analogue or digital PCM)

nMono

The AVR250 will remember which mix mode was last used with a two-channel source and, if ‘Surround’, which particular surround mode. See ‘Two Channel Source Modes’ for more information. If an effect mode has been applied whilst in Stereo, this will also be remembered.

There is a link between the mix modes for multi-channel bitstream (e.g., 5.1) and two-channel bitstream (2.0 or 2.1) sources. If a 5.1 source is played in Surround mix mode, the AVR250 will remember this for all bitstream sources (e.g., DTS-ES Matrix, Dolby Digital 3.0 etc.) and use the maximum number of speakers the signal is encoded for. As a result, when a 2.0 or 2.1 bitstream is played the Surround mix mode is recalled and the AVR250 enters Dolby Pro Logic IIx Movie mode to try to recreate the surround environment from what may be a Pro Logic encoded source. If you would rather listen to a 2.0 or 2.1 bitstream in ordinary stereo (with or without a subwoofer), press MODE to cycle through to the Stereo mix mode (e.g., Dolby Digital 2/0.0 on the display). However, if the source becomes multi-channel bitstream (e.g., 5.1) again, the AVR250 will recall Stereo mix mode and therefore output a Stereo Downmix of the multi-channel signal. Full surround output can be re-achieved by pressing MODE to cycle through to the surround mode encoded on the disc.

Digital multi-channel sources

Digital multi-channel source material is normally provided as ‘5.1 audio’. The ‘5.1 channels’ comprise of: left, centre and right front speakers, two surround speakers and a low frequency effects (LFE) channel. Since the LFE channel is not a full range channel, it is referred to as ‘.1’.

Surround systems decode and reproduce the 5.1 channels directly. Dolby Digital EX and DTS-ES enhanced decoding systems create one extra rear channel from information buried in the two surround signals of the 5.1 source. These EX and ES enhanced systems are sometimes referred to as ‘6.1’ systems. This extra surround back channel is normally reproduced through two separate loudspeakers, creating a ‘7.1 system’.

5.1 Playback on 7.1 speaker systems

When listening to 5.1 channel digital recordings, such as Dolby Digital and DTS on a 7.1 channel speaker system you will have two speakers producing no sound. These two surround back speakers can be assigned the same signal as the surround speakers in the ‘Speaker Sizes’ page of the Set-up Menu. When both the surround and surround back speakers are selected the volume from both will be reduced by 3 dB to keep the sound levels in balance.

English

AVR250

E-25