CX233 I
NSTALLATION AND OPERATION MANUAL
3
3.02
Gain Control
Pre-set gain controls are provide adjacent to the respective XLR input connector. The
gain can be adjusted from 6dB to 60dB of gain. The wide range of gain allows direct
connection of high output devices such as radio microphones without the need for input
attenuators. A high overload margin of 20dB is maintained at all gain settings.
3.03
Front Panel Level Controls
These are provided for the user to set the desired signal level and are often used by an
unskilled operator. It is suggested that the gain control on the rear panel is set at a level
where it is not possible to have excessive gain even when the front panel level control is
fully clockwise. Self adhesive labels are provided to customise the controls.
3.04
Priority
Both microphone inputs have optional automatic priority. When a microphone is used
with the priority operative, any music signal which is present will be attenuated. Normal
music operation will be restored smoothly after the announcement has been made. The
respective priority switch is positioned to the right of the zone select switches and is
marked "PR".
3.05
Equalisation
Comprehensive equalisation is provided for the microphone signals and common controls
are used for both channels. The treble control (HF) has a range of ±10dB at 5kHz and
the bass control (LF) has a range of ±10dB at 100Hz. In addition to the treble and bass
controls, a contour switch is provided. This can be used to improve intelligibility of
speech particularly when Hi-Fi loudspeakers are being used. The "contour" switch
introduces a boost of 6dB at 3kHz.
3.06
Emergency Mode
This facility operates on Mic 2 input only and is primarily for the purpose of interfacing a
dedicated evacuation microphone or evacuation message player. When the "emergency"
mode of operation is selected, the Mic 2 input is normally muted and becomes active in
all 3 zones when the fire alarm is activated.
4
Zone Outputs
4.01
Zone Outputs
All three stereo zone outputs are balanced and can operate with loads as low as
600 ohm. 3 pin XLR type connectors are used for all outputs. The nominal output is
0dBu (775mV) but the CX233 can operate satisfactorily with a wide range of signal levels
up to a maximum balanced output of +26dBu. If you are connecting any zone output to
an unbalanced input see section 9.02 "Unbalanced Mode".
4.02
Equalisation
All three zone output circuits have independent treble (HF) and bass (LF) controls. The
treble control has a range of ±10dB at 10kHz and the bass (LF) control has ±10dB at
50Hz. These controls can be used to provide compensation for differing acoustics or
loudspeaker types.
