Sound Devices 302 - Manual (Page 16)

302 User Guide and Technical Information
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v. 3.6 Features and specifications are subject to change. Visit www.sounddevices.com for the latest documentation.
The Meter
The 302’s meter provides a great deal of audio signal information to the operator. The ability to
view multiple ballistics, peak levels (PPM), average levels (VU), or a combination of both, is unique
to Sound Devices LED-based meters. The 302 meters do not share the inherent limitations of LCD
and mechanical meters. LCD-based meters can have sluggish indications in cold temperature.
Mechanical meters can be fragile and not ideal for field use.
The 302 meters share the same technology and software programmability used in Sound Devices
larger 442 field mixers and on the 7-Series digital recorders.
Source
The meter can display levels of the output buses, the PFL levels, or RTN Input levels. Default
operation is always the output bus except when PFL’s are selected from the Headphone Selection
Switch. This operation can be modified in the Setup Menu.
Press to cycle through available
meter ballistics selections
Press to change
LED brightness
Scale
When viewing peak information on the meter, its scale is calibrated in peak-reading dBu. When
viewing VU (Volume Units) information, its scale corresponds to VU units.
Unlike other analog mixers, the 302 is calibrated with its 0 VU reference at 0 dBu, not +4 dBu. If you
primarily interconnect with analog video cameras, you may want to change the 0 VU reference to +4 dBu
in the Setup Menu.
The 302’s scale is designed for digital recording devices, providing maximum information between
-30 dBu to 0 dBu which is where typical peaks occur (-50 to -20 dBFS). This allows the user to record
with a full 12 to 20 dB of headroom while in the fine-resolution green-colored part of the meter.
Additionally, the meter color changes to orange at 0 dBu and red at +8 dBu. These color changes
correspond to -20 dBFS and -12 dBFS respectively, which are commonly used recording levels for
today’s digital recording devices.
IRT Scale Compliance
The 302 meter scale can be shifted to comply with the German IRT specifications. Setup Menu item
-8 controls the adjustment to shift the meter scale. See http://www.irt.de/ for more information.
Ballistics
Meter Ballistics refers to way the LED Meter visually displays the behavior of an audio signal.
Pressing the PK/VU button on the 302’s front pane will instantly display the next ballistic setting. At
Factory Default, the ballistics are displayed in this order VU, Peak, Peak-Hold and VU combination,
and Peak and VU combination. The selection and order of the various ballistics can be altered in the
Setup Menu. See Setup Menu for more details.