Universal Audio Apollo x4 Hardware Manual page 23

(3) Channel Selection Indicators
The currently selected input channel is indicated by the lit channel name (CH1, CH2,
CH3, or CH4) above its input meter. Press the PREAMP button (10) to change the
selected input channel.
(6) Input Meters
The four input meters display signal levels for each of the analog input channels. Reduce
a channel's preamp gain (see
(5) Input Source Indicators
These indicators show which input source jack (MIC, LINE, or HI-Z) is active for the
selected input channel. Use the Input Select button (8-a) to switch between the
MIC (XLR) and LINE (¼") rear panel combo jack inputs. The Hi-Z input is selected
automatically when an instrument cable is plugged into the Hi-Z jack on the front panel.
(11) Talkback Microphone
The built-in talkback mic is located inside of this hole. The talkback function is
configured in the companion Console software and can be activated with the TALK
button (8-g) when Monitor mode is active.
Caution: The talkback microphone is sensitive. To avoid equipment damage, do
not insert any object into the mic hole, apply pressurized air into the mic hole, or
use a vacuum over the mic hole.
(10) PREAMP Button
Press this button to enter
again change the selected input channel (3).
(5) Selected Stereo Output
These indicators display which stereo output (MONITOR, HP1, or HP2) is currently
selected for volume control with the Level knob (1). Press the MONITOR button (12) to
change the selected stereo output (you may need to push it more than once).
Note: The MONITOR indicator is RED when the monitor outputs are muted.
(9) Stereo Output Meters
These meters display the main stereo signal output bus levels.* The main output bus
levels are independent of monitor and headphone volume levels. Reduce levels feeding
the output(s) if a red "C" (clip) LED at the top of the Output Meters illuminates.
*Exception: If a HP output is currently selected on Apollo x4 and the HP Source
within the CUE OUTPUTS window in Console is set to the same HP output, these
output meters indicate the level being sent to the headphone bus via Console's
headphone sends and/or the DAW.
Apollo x4 Hardware Manual
Set Input Gains) if its red clip LED illuminates.
PREAMP Mode and activate the input channel controls. Press
23 Controls & Connectors