INTRODUCTION
The T L Audio Crimson Series utilises low noise solid state circuitry to produce audio
processing units offering very high quality signal paths with comprehensive control
facilities. Crimson series units are straight-forward to operate, and offer excellent
value for money.
The VP-3051 is a single channel voice processor, combining a high quality
microphone pre-amplifier, four band equaliser and a compressor. All parameters of the
compressor are variable, and a link facility enables two units to be operated in stereo
mode. The bargraph meter may be used to display output level or gain reduction.
The block diagram of the unit is shown in fig.1. Each channel has four input sources -
balanced microphone and line inputs via XLR connectors, plus an unbalanced line
level input via a jack socket, and an instrument input also on an unbalanced jack
socket but located on the front panel where it provides a convenient means of patching
a guitar or keyboard directly into the processor. The gain of the input stages is
controlled by a centre-detented control, calibrated for 0dB nominal gain from the line
input sources at the centre and providing up to 60dB of microphone gain. The
instrument input has a sensitivity switch associated with it, to match the gain to a low
level pickup (e.g. a passive guitar or microphone) or a higher output source such as a
keyboard or active guitar, and is also controlled by the input gain potentiometer.
The equaliser has four bands, providing up to 15dB of cut and boost at the selected
frequencies. The “EQ PRE” switch positions the equaliser before (pre) or after (post)
the compressor. The sidechain monitors the output of the compression stage, and
generates a control signal which varies the attenuation of the compressor. The
sidechain processing includes fully variable control of the compressor threshold and
ratio, plus switched fast and slow time constants for attack and release. Frequency
dependant compression (for example de-essing) may be achieved by placing an
equaliser into the sidechain insertion point.
An independent gain make-up control is provided, to retain the subjective loudness of
a compressed signal, plus an overall master output level control. The output control
has a nominal 0dB of gain at its centre, with up to 18dB of further gain available to
ensure full modulation of digital recorders. The output is via a balanced XLR socket at
a nominal level of +4dBu, with an unbalanced output on a jack socket at a nominal
level of -10dBu. An LED bargraph meter is provided, which may be switched to
monitor the output signal level or compression applied.
Please read this manual fully before installing or operating the Voice Processor.
