Operation Manual

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PRO Series Live Audio Systems
Owner’s Manual
Appendix A: Application Notes
This chapter provides more in-depth information on certain areas and functions of the
PRO Series.
Spatial imaging system (SIS™)
Although conventional consoles can be used for three-channel mixing, the methods for
doing so are complicated and unorthodox. This forces the engineer to work in
unaccustomed ways, limiting creative flexibility, and making use by visiting operators
impractical. The spatial imaging system (SIS™) has been developed to overcome this.
The following are just some of the advantages provided by SIS™:
• Backing vocalists can be panned slightly towards the centre cluster to improve
intelligibility, while keeping the featured vocal ‘front and centre’.
• Musical instruments can be placed in a conventional mix and then easily switched to
the centre for solos.
• In theatrical productions, SIS™ lets you pan an actor’s voice across three channels,
following their on stage movements. In stereo-only productions the centre output
can be used to provide a mono-to-mix-base feed activating a single ‘left + right to
centre’ switch.
• The ability of SIS™ to feed centre-panned signals equally to both left and right
outputs, as well as the centre, is particularly useful for distributing the load of high
energy, centre-panned sounds across all FOH loudspeaker arrays.
PRO Series compressor modes (dynamic)
This section aims to provide an understanding of the compressor modes contained
within the PRO Series Control Centre.
Description
The PRO Series compressors have five primary operating modes (only four on the
inputs). These change the signature (or shape) of the attack and release envelope
curves, interactions and timings. Before dealing with this in detail, some of the generic
terms are defined and explained:
Threshold
The threshold adjusts the operating point of the compressor. Signals that go over this
point, or over-threshold, will be affected by compressor action. Signals that stay below
threshold will not trigger any compression, although they may still be affected by
compression releases from previous over-threshold signals.
Ratio
The compression ratio control provides control of the amount of compression that is
applied to over-threshold signals. This is expressed as a ratio of signal level changes
from input to output. For example, when the compressor is set to 2:1, every 2dB input
level change will only generate a 1dB output level change (assuming the signal levels
are over-threshold).