Sound Devices 664 - Manual (Page 16)

Polarity reversal is used to compensate for incorrectly wired balanced cables, to prevent signal can-
cellation when a source is dual-miked from opposite directions, or to reverse left/right with micro-
phones in a mid-side (MS) configuration.
Phantom Power
Phantom powering is a fixed DC voltage of either 12 or 48 Volts. This voltage is resistively applied
to pin 2 and pin 3 of an input’s XLR-3F connector, relative to pin 1. In this configuration, there is no
voltage difference between signal pins 2 and pin 3.
The phantom voltage is selectable between 12 and 48 Volts from the Setup Menu item
INPUTS > Phantom Voltage. The selected voltage level applies to all inputs with phantom power
enabled. The factory default phantom power voltage is 48 V.
Phantom power can be activated for each input. To enable phantom power, enter the input’s chan-
nel screen, press the Headphone Controller, highlight either MIC-PH or LINE-PH, press Headphone
Controller again to make the selection.
Gain/Trim and Fader Relationship
The gain of an input is adjusted by two controls, Input Trim and Input Fader. This two-stage archi-
tecture is identical to the topology of large mixing consoles and provides a great deal of control.
Input Trim is often thought of as a course gain control and the Input Fader as the fine gain control.
Input Trim (Analog)
The 664’s analog input sensitivity is set with the pop-up Trim control
knob. With the Input Fader set to unity gain (0 dB or 12 o’clock), make
the appropriate adjustments using the Trim control. Once the coarse gain
is set to the desired level, press the Trim control to hide it from the 664’s
mixing surface. Analog trim level is adjustable from +22 to +72 dB of gain.
Input Trim (Digital)
The coarse level of a digital input is set by rotating the Select Encoder in
the Input Settings Screen of an input with a digital source. The digital
trim level is displayed on the LCD when adjusted. The digital trim level is
adjustable from -20 to +50 dB.
Input Fader
The Input Fader is the primary control used while mixing and it affects
the level of the Input signal routed to all post-fade destinations. Use the
Input Fader to make fine gain adjustments. The fader can be attenuated
from off (full counter-clockwise position) to +15 dB above the set Trim
level (full clockwise position). To optimize gain structure for the best per-
formance, operate input faders at or near the 0 dB (unity gain) position.
664 User Guide and Technical Information
v. 2.02 Features and specifications are subject to change. Visit www.sounddevices.com for the latest documentation.
10
In
put Se
tup & Contr
ol