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DSP presets for two-channel material
The G68 provides several signal processing options for two-channel
material. The Music DSP presets are designed for use with music
from sources such as CD, radio, or two channel DVD-A:
•Music, Trifield, Ambisonics, Super Stereo, Music Logic, PLIIx Music,
Stereo, and Direct.
The Logic DSP presets are designed for use with film soundtracks
or TV programmes:
•PLIIx Movie, PLIIx THX, TV Logic, and Mono.
The Music and Logic DSP presets use the Music and Logic speaker
layout respectively; see
Speaker layouts
, page 43.
Music
The Music DSP preset extracts the mono and surround components
of the original recording. These components provide an alternative
representation of the original sound, and this is sometimes used
for recording systems or in broadcasts such as FM radio. The mono
element is equalised using a proprietary Meridian technique to
match the tone colour of the centre speaker, and to compensate
for the fact that the frequency response of human hearing changes
with direction.
The Music DSP preset is recommended for recordings made with
spaced omnidirectional microphones, or using a mono-surround
technique.
Trifield
As for the Music DSP preset, the Trifield preset extracts the mono
and surround components of the original recording. It then
calculates the signals for the front, left, centre, and right speakers,
using the phase and amplitude differences between the three front
channels, to redistribute the sounds on a frequency-dependent basis.
This gives a significant improvement over traditional stereo, which
converts the differences between the microphone signals into
amplitude differences in the speaker signals. This version of the
Trifield algorithm is virtually impossible to implement without
digital signal processing.
Trifield is recommended for well-made recordings and stereo
television broadcasts that are not Dolby Surround encoded. An
advantage over the Music DSP preset is that the front stereo image
is more focused, and the width of the image can be adjusted.
Music and Trifield DSP preset parameters
Parameter Options What it changes
Centre Flat, EQ1-3 The timbre of the centre loudspeaker.
Width† 0-1.5 The width of the image.
Surr. Rear Surr. Rear, Surr. Side, Surr. All Switches the surround signal between the side and rear speakers.
R Filter Off, 1kHz, 3kHz, 7kHz The cutoff of high frequencies from the rear surrounds.
S Filter Off, 1kHz, 3kHz, 7kHz The cutoff of high frequencies from the side surrounds.
†Trifield only.
DSP presets
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G Series DSP 45 31/10/03, 4:24:38 pm