Solid State Logic SSL 12 USB Audio Interface - Manual (Page 26)

With ALT SPK ENABLE (5) engaged, engaging the ALT button will transfer the
MASTER BUS signal to Outputs 3&4 .
7. DIM LEVEL
The DIM LEVEL control adjusts the level of attenuation provided when the DIM (1)
button is engaged. This allows up to -60dB of attenuation when fully tuned counter-
clockwise.
8. ALT SPEAKER TRIM
The ALT SPKR TRIM knob allows gain adjustment to offset the output level sent to
the ALT monitors connected to Outputs 3&4. This allows the levels to be adjusted
between the Main Monitors and Alt Monitors so the Monitor Control level doesn't
need to be changed when A/Bing between two different sets of speakers for a more
accurate comparison.
SETTINGS
In the bottom-right of the SSL 12 Mixer, you can access the Settings panel, which
contains configuration options for the Headphone outputs and also Peak metering.
HEADPHONE OUTPUTS MODES
The HP outputs can operate in one of 2 modes:
Headphones Mode
Line Output Mode
Headphones Mode Options
When operating in Headphones Mode, you can choose between 3 different options:
Standard - The default setting and is suitable for a wide range of headphones.
High Sensitivity - This is most applicable for use with certain In-Ear Monitors
(IEMs) or headphones that have especially high sensitivity (expressed in
dB/mW). Typically, headphones that specify their performance at 100 dB/mW
or higher.
High Impedance - This setting is ideal for High Impedance headphones which
require greater voltage drive to produce the expected output level. Typically,
headphones with an impedance of 250 Ohms or greater will benefit from this
setting.