Owner's manual

Headphone Monitoring
Headphone Gain
By default, headphone output level is controlled by turning the Headphone Encoder while viewing
the Main Screen or Input Settings Screen. When adjusting the headphone gain, the gain value (in dB)
is displayed in the lower right corner of the LCD (Near the Headphone Encoder). This space dis-
plays the currently selected headphone source when the headphone gain is not being adjusted.
Headphone Encoder
Headphone gain during adjustment
The 664 can drive headphones to dangerously high volumes. Turn down the headphone gain
before selecting a headphone source to prevent accidental signal extremes.
Headphone Source Selection
By default, to select the monitor source: Press the Headphone Encoder while viewing the Main
Screen. This will display a list of available monitor sources. Turn the Headphone Encoder to high-
light a source, and press the Headphone Encoder to select that source. The signal to the headphone
outputs will immediately change to the selected program.
Monitor Source Description
LR ST Master Bus in stereo.
LR Mono Master Bus summed mono to both ears.
L Mono Left channel of Master Bus sent to both ears.
R Mono Right channel of Master Bus sent to both ears.
LR MS ST Mid-Side Stereo - Master Bus decoded MS stereo to headphones, this is not to be used if the inputs
are already linked as an MS pair.
X1X2 Aux Bus in stereo.
HP Preset HP Presets 1-10 are customizable monitor sources. See Headphone Presets
The visibility of presets in the Headphone Source selection menu can be toggled individually from Setup
Menu option SYSTEM > Headphone Preset List.
664 User Guide and Technical Information
v. 2.02 Features and specifications are subject to change. Visit www.sounddevices.com for the latest documentation.
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Headphone Monitoring