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AM821X / AM1221X / AM1621X / AM2421X
CHANNEL CONTROLS
18. Low Cut Filter (75 Hz)
This button, located on all mono chan
-
nels, will active a 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.
19. PAD Button (Stereo Channels Only)
This button, located on channels the final 4 mono chan
-
nels of all models, attenuates the input signal of the Mic or
Line inputs by 20 dB. This gives a greater dynamic range
to the input, allowing inputs with higher-level signals to be
used without the possibility of clipping.
20. Gain Control
This controls the sensitivity of the input signal of the Line/
Microphone input of mono channels. 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 al
-
low the peak indicator occasionally illuminate or slightly
lower than this.
21. 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.
22. Middle Frequency Control
This control is used to provide a peaking style of boost
and cut to the level of middle frequency sounds at a range
of ±15 dB. The mixer also provides a sweep control, al
-
lowing you to select a center frequency between 100 Hz
and 8 kHz. Changing middle frequencies of an audio feed
can be rather difficult when used in a professional audio
mix, as it is usually more desirable to cut middle frequen
-
cy sounds rather than boost them, soothing overly harsh
vocal and instrument sounds in the audio.
Stereo channels differ slightly, in that they feature a High
Mid and Low Mid control for adjusting Middle Frequency
sounds with set frequencies of 3 kHz and 800 Hz.
23. Low Frequency Control
This control is used to give a shelving boost or cut of ±15
dB to low frequency (80 Hz) sounds. This will adjust the
amount of bass included in the audio of the channel, and
bring more warmth and punch to drums and bass gui-
tars.
24. AUX Controls
These two AUX controls alters the signal level that is be-
ing sent to the auxiliary 1 and 2 mixing buses, the signal
of which is suitable for connecting stage monitors, allow
-
ing artists to listen to the music that is being played, or to
fed to an external effect processors.
25. EFX 1 and 2
These two controls adjust the level
of audio sent from the channel to
the EFX 1 and 2 mixing buses.
The EFX 2 signal is also sent to
the built-in digital effects proces-
sor, allowing users to apply effects
to the signal.
26. Pan/Balance Controls
This alternates the degree or level
of audio that the left and right side
of the main mix should receive. On
mono channels, the PAN control
will adjust the level that the left and
right should receive (pan), where
as on a stereo channel, adjusting
the BAL control will attenuate the
left or right audio signals accord-
ingly (balance).
27. Mute Button
This button mutes the channel,
effectively stopping all audio fed
into the inputs from being send
to the Main L/R mixing bus, as
well as the AUX 1, AUX 2, EFX
1 and EFX 2 mixing buses. This
indicated just below the button
(labeled Peak) will be illuminated
when the channel is muted.
28. Peak Indicator
This LED indicator (which doubles
as a mute indicator) will illuminate
when the channel hits high peaks,
6 dB before overload occurs. It is
best to adjust the channel level
control so as to allow the PEAK in-
dicator to light up on regular inter-
vals only. This will ensure a greater
dynamic range of audio. This indi-
cator also doubles as a Mute in-
dicator, when the channel’s mute
button is engaged.
29. Sig Indicator
This LED indicator shows when the input level reaches
-20 dBu, basically showing when a signal is received by
the corresponding channel.
30. PFL Button
The PFL - or Pre-Fader Listen - button is pushed to al-
low the signal of a channel to be sent to the CTRL RM/
PHONES mix (pre-fader, post-EQ), for use with either
headphones or studio monitors. This allows easier set-
ting of the input gain and tracking of audio by sound engi-
neers. The Sig LED above the button will illuminate when
PFL is activated.
31. Channel Level Control
This 60 mm fader will alter the signal level that is sent from
the corresponding channel to the Main L/R mixing bus.
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