Drawmer SL22 Sound Level Limiter - Manual (Page 9)

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POWER LED
When lit indicates that the SL22 unit is switched on.
LEFT CHANNEL INPUT / OUTPUT
The left channel from the mixing desk/console/pre-amplifier etc. should connect to the input here.
The output should connect directly with the left channel Active Monitor/ Amplifier & Speaker. Once leaving the SL22
this signal can be attenuated, but no gain should be added.
Balanced connections are recommended.
RIGHT CHANNEL INPUT / OUTPUT
The right channel from the mixing desk/console/pre-amplifier etc. should connect to the input here.
The output should connect directly with the right channel Active Monitor/ Amplifier & Speaker. Once leaving the SL22
this signal can be attenuated, but no gain should be added.
Balanced connections are recommended.
HEADPHONE OUTPUT
A 1/4” stereo headphone output is provided on the rear panel. This limits the audio in the same way as the channel
outputs and will protect your hearing and headphones in an identical manner. In order to comply with noise at work
regulations and to protect your hearing to maximum listening levels the headphone volume level should be calibrated
(see calibration section).
EXTERNAL / FIRE ALARM I/P
The ability to have some external control over volume levels has been provided via these connectors.
DIM - when activated attenuates the signal volume by 20dB. In other words, DIM lowers the Max Volume control
setting by 20dBs - and so the SL22 will still protect in exactly the same manner.
MUTE - when activated attenuates the signal volume by 70dB.
The uses for this facility are widespread and could be used to allow for voice overs to be heard more clearly, for
example, or to lower the volumes of a nightclub at certain times to comply to local authority noise regulations. A Fire
Alarm could be connected directly to the SL22 via these connections to attenuate or mute the audio and allow for the
alarm to be heard more clearly in the case of a fire.
In order to trigger either connection the circuit has to be closed externally - this can be done in the form of a physical
switch, or via relays etc. The connections are via bare wire screwing terminal blocks.
Contact the Drawmer technical department for further information.
EXTERNAL INDICATOR OUTPUT
Facilitates the use of external indicators that provide a visual reflection of the level of limiting that is occurring within
the SL22. They could be connected to a light on a wall or office, or more sophisticated instrumentation. As well as
visual indication, the External Indicator Outputs could also be used for data logging to help further adhere to noise at
work regulations.
ALERT and PROTECT are isolated solid state relays which switch on in conjunction with the corresponding LEDs
on the front panel. In order to operate external power of a maximum 24V at 50mA should be applied across the
terminals by the external indicator.
TRIGGER operates in conjunction with the Protect LED indication on the front panel. It differs from the Alert and
Protect connectors in that it supplies its own power of 5V and could be used to trigger an external warning device.
The connections are via bare wire screwing terminal blocks.
Contact the Drawmer technical department for further information.
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