Allen&Heath ML3000 USER GUIDE - Manual (Page 39)

ML3000 User Guide 39
OSC/NOISE GENERATOR
WARNING
: The generator is capable
of producing a high level continuous signal. To
avoid damage to the speakers check that the
generator and output levels are turned down
before you route the test signal to the outputs.
OSC/NOISE TRIM. Adjusts the level of the
oscillator or noise signal from –30 to +10dB.
OSC/NOISE SELECT. In its up position pink noise
is selected as the generator source. Press to select
the 1kHz test tone.
Pink noise. This is a constant level random noise
signal with equal energy per octave covering the full
audio bandwidth.
1kHz Oscillator. This produces a pure 1kHz tone
(sine wave) for single frequency testing and line up.
OSC/NOISE TO TB. Press this switch to route the
pink noise or 1kHz tone test signal to any
combination of LR, C and Grp/Aux outputs that
have their TB switches selected. The switch has a
latching action so that it can remain selected while
testing and calibrating the speakers.
DISABLE. Press the underpanel switch to disable
the osc/noise generator. This protects against
accidental operation during live performance.
Using the Osc/Noise Generator
Start with the TRIM control turned down. Select
either pink noise or the 1kHz tone as the test signal.
Check all the TB enable switches are correctly set
to route the signal to the required outputs. Make
sure the DISABLE switch is up (flush with the
panel). Press OSC/NOISE TO TB to route the
signal to the selected outputs. Raise the TRIM
control and output faders to achieve the level
required. The test signal should register on the
console meters in the normal way.
Use pink noise to test the speakers for correct
operation. This is made up of the full audio
bandwidth and can test all the drivers at the same
time. Used with a reference microphone and RTA
(real time analyser) you can check the venue
acoustics for frequency response.
Use the 1kHz tone to check matching and line up
between equipment by adjusting input and output
levels using the meters as the reference.
When you have finished using the generator be
sure to disable it if you want to avoid the possibility
of accidental operation during performance.
OSC/NOISE
1kHz OSC
PINK NOISE
Disable
TO TB
min max
OSC/NOISE
TRIM