Meridian Audio 861 - Manual (Page 33)

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DSP Presets
Ambisonic surround sound is quite unlike conventional
stereo. A special microphone can be used to capture
the sound of the original performance in all three
dimensions, allowing a recording to be made in a
special format (B-Format) that describes the soundfield
exactly at the microphone position. Alternatively,
special mixing techniques including Ambisonic spatial
localisation controls (panpots) can be used to mix
conventional multitrack into the same Ambisonic
surround format. The channels of this recording can
then be encoded using a phase-amplitude matrix (UHJ)
to allow the surround information to be conveyed,
typically via a two-channel medium such as disc or FM
broadcast. On playback, the decoder reconstructs the
soundfield captured by the original recording.
The digital surround controller uses accurately matched,
frequency-dependent, phase-amplitude matrices to
decode the signal and construct the signals for each
speaker feed.
The fundamental difference between Ambisonics
surround sound and conventional stereo is that the
signals from all the speakers combine to produce a
coherent soundfield at the listening position, giving the
illusion that you are sitting inside the recording space
whether you are at the exact central seat or well off to
one side.
Of all the signal-processing options, Ambisonics is the
one that requires the greatest attention to speaker
choice and positioning.
Super
Super synthesises a signal from a conventional stereo
recording or broadcast so that it can be decoded using
the Ambisonic decoder. The result is especially effective
for two particular types of recordings:
Those using true coincident microphone techniques.
Multi-tracked or multi-miked recordings. •
•
Ambisonics and Super DSP preset
parameters
Parameter Options What it changes
Width* 0 to 1 The width of the image.
Row† A, C, E, G, I,
K, M The seating position;
the letters are like rows
in a hall.
Channels 7, 6, 5, 4 The number of
speakers.
R Filter Off, 3kHz,
7kHz, 9kHz The cutoff of high
frequencies from the
rear surrounds.
S Filter Off, 3kHz,
7kHz, 9kHz The cutoff of high
frequencies from the
side surrounds.
* Super only.
† Ambisonics only.
MusicLogic
MusicLogic is a music DSP preset based on Pro Logic
II with the addition of user-adjustable steering, designed
to provide an exciting experience with many types of
studio-produced music.
MusicLogic DSP preset parameters
Parameter Options What it changes
Roll Off, Low,
Med, Max The degree of left-right
steering.
Yaw Off, Low,
Med, Max The degree of front-rear
steering.
Steered All Steered Rear,
Steered Side,
Steered All Which of the four
surround channels are
generated by steering.