The Pfl (Pre Fader Level) Section; The Level Meter Section; The Crossfader Section - Alto MX-20 User Manual

3.1.3 The PFL (pre fader level) Section

When you connect a headphone to your MX-20 you have
the chance of pre-listening the audio signal before the signal
reach the main output.
-. LEVEL Control
This knob will adjust the volume of the headphone signal.
-. The MIX Control
Through this control, you can mix the signal between
CH1 and CH2.

3.1.4 The LEVEL METER Section

-. MAIN/PFL Switch
When this switch is in MAIN function (MAIN LED on) the
level Meter will display the output level of the left and
right channels;
When this switch is in PFL function (PFL LED on) the
level Meter will display the PFL headphone signal:
channel 1 on left LED meter and channel 2 on right LED
meter.
-. LEVEL METER
This 10 segments LED's Meter will read the signal selected
by the MAIN/PFL switch. Please see above.

3.1.5 The CROSSFADER Section

-. The FADER Control
Through this crossfader you can fade in between channel 1
and channel 2. The crossfader on your MX-20 is User
replaceable.
9
10
11
12
13
7
PFL
MIN MAX
LEVEL
CH1 CH2
MIX
MAIN PFL
MAIN / PFL
LEVEL METER
+10
+7
+4
+2
0
-2
-4
-7
-10
-20
CH 1
13
9
10
11
12
CH 2