User guide

DSP presets

Logic DSP presets

The digital surround processor provides six DSP presets

specifically designed for reproducing stereo film soundtracks.

PLII Movie and PLII THX use the new Dolby Pro Logic II DSP

processing mode, and are the recommended choices for Dolby

Surround encoded material. Most films, and many TV

programmes and series, are encoded using Dolby Surround,

and it is increasingly being used to encode music.

Pro Logic, THX Cinema, and TV Logic are based on the original

Dolby Pro Logic DSP processing mode, and are also designed

for Dolby Surround encoded material.

The remaining Logic preset, Mono is designed for films with

mono soundtracks.

Pro Logic II

Dolby Pro Logic II is a new decoding mode designed for any

two-channel source, whether or not it is encoded for Dolby

Surround. It can also be used for two-channel Dolby Digital

sources

It re-creates 5.1-channel movie surround from the two-channel

source, using improved decoding techniques that preserve the

directness of the sound field, resulting in enhanced image

stability compared with standard Pro Logic decoding.

Meridian’s implementation of Pro Logic II was the first in the

world to receive Dolby approval, and uses proprietary code

based on 48-bit precision to give outstanding clarity.

PLII THX

The PLII THX DSP preset provides Pro Logic II decoding,

followed by additional signal processing refinements developed

by Lucasfilm Ltd. These are designed to provide a better match

between the sound of the movie theatre and a home cinema in

the following ways:

❍ The front channels are re-equalised to correct for the higher

treble often found in film soundtracks.

❍ The surround channels are frequency-corrected using a

timbre-matching process so that sounds moving front–back

are more convincing.

❍ The surround channels are decorrelated to break up any

artificial localisation of the rear signals due to the speakers

being nearby. In the 568.2 Digital Surround Processor this

decorrelation is optimised to give spacious surround sound

that has no artefacts disturbing to music or other sensitive

sounds in the mix.