Meridian 568 User Manual page 49

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.
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Music and Trifield DSP preset
parameters
Parameter Options
HS Out? * Y or N
Centre Flat, EQ1 to 3
Width † 0 to 1.5
Surr. Rear Surr. Rear,
Surr. Side, Surr. All
R Filter Off, 1kHz, 3kHz,
7kHz
S Filter Off, 1kHz, 3kHz,
7kHz
* Y gives high-rate audio to the front speakers (left, right, centre,
and subwoofer) upsampled if necessary. N gives standard-rate
audio using all speakers, downsampled if necessary.
† Trifield only.
What it changes
High-rate audio.
The timbre of the
centre loudspeaker.
The width of the image.
Switches the surround
signal between the
side and rear speakers.
The cutoff of high
frequencies from the
rear surrounds.
The cutoff of high
frequencies from the
side surrounds.