Rear Panel
10. Main L and R Outputs
These two ports will output the final stereo balanced line level
signal sent from the main mixing bus. The primary purpose of
these jacks is to send the main output to external devices, which
may include power amplifiers (and in-turn, a pair of speakers),
other mixers, as well as a wide range of other possible signal
processors (Equalizers, Crossovers, etcetera).
11. Control Room Outputs
These two 1/4" Phone Jack outputs feed the signal altered by
the Control Room/Phones level control on the face of the mixer.
This output has extensive use, as it can be used to feed the
signal from the mixer to an active monitor, for the monitoring of
the audio signal from within a booth, among other possible uses.
12. ALT 3-4 Output
These unbalanced outputs are fed from the ALT 3-4 mix and
can be used in conjunction with a large array of input devices,
including signal processors, recording devices, monitor mixers,
and so on. The ALT 3-4 mix is created by muting signals on
channels 1 through 8.
13. USB Connector (AM1204FX USBR Only)
This USB connector can be used to connect the AM1204FX
USBR to any modern Windows or Mac-based computer. Doing
so will allow users to get a stereo signal both to and from the
computer.
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CONTROLS AND SETTINGS
Back Panel
14. Power Switch and AC Connector
The power switch, located on the rear of the mixer, is used to
activate the mixer. But there's no point in activating the mixer
if there's no power, therefore an AC power connector has been
included to ensure your mixer gets the power it needs. Please
use the power cable that is included with this mixer only.
15. Phantom Power Switch
When this switch is in the on position, it activates +48V of
phantom power for all microphone inputs, allowing condenser
microphones (well, the ones that don't use batteries) to be
used on these channels. Activating phantom power will be
accompanied by an illuminated LED above the left channel level
meter. Before turning Phantom Power on, turn all level controls
to a minimum to avoid the possibility of a ghastly popping sound
coming from the speakers.
NB. Phantom Power should be used in conjunction with balanced
microphones. When Phantom Power is engaged, single ended
(unbalanced) microphones and instruments should not be used on the
Mic inputs. Phantom Power will not cause damage to most dynamic
microphones, however if unsure, the microphone's user manual should
be consulted.
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Channel Controls
16. Low Cut Filter (75 Hz)
This button, located on channels 1 through to 4, will activate a
low-cut / high-pass filter that reduces all frequencies below 75
Hz at 18 dB per octave, helping to remove any unwanted ground
noise or stage rumble.
17. Gain Control
These controls, found on each input channel, allow users to
adjust the sensitivity of the input signal for the Line/Microphone
input. The gain should be adjusted to a level that allows the
maximum use of the audio, while still maintaining the quality of
the feed. This can be accomplished by adjusting it to a level that
will allow the peak indicator occasionally illuminate. All 4 mono
channels feature this control.
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18. Compressor Controls and Indicators
These control the onboard compressor function on mono
channels. Turning this control up towards the 12 o'clock position
will adjust the threshold and ratio of the compressor at varying
degrees. Once you reach the 12 o'clock position, the control
will then adjust the compression settings along with an onboard
expander (or, in other words, a "compander"). The LED that
accompanies this control will light up when the compressor is
triggered. This control and indicator can only be found on mono
channels.
19. High Frequency Control
This control is used to give a shelving boost or cut of ±15 dB to
high frequency (12 kHz) sounds. This will adjust the amount of
treble included in the audio of the channel, adding strength and
crispness to sounds such as guitars, cymbals, and synthesizers.
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AM1204FX / AM1204FX USBR
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