Audio Levels - NewTek TriCaster 40 User Manual

3.9.1 AUDIO LEVELS

TriCaster's analog audio conforms to SMPTE RP-155. The maximum input/output level is +24 dBu. Nominal
input level is +4 dBu (-20dB FS), and the sample rate is 48 kHz.
Levels above 0dB are shown in red in the VU meters, to caution you that overly high levels can result in clipping
in recordings.
Hint: An error message appears in the Status Bar above the main Program output monitor to warn you if clipping
occurs.
VU METERS AND GAIN
A large portion part of both audio mixers is devoted to VU (Volume Unit) meters. These
displays vary depending on the source type. For Input 1, the meter displays the levels for
the two analog input channels, controlled by a single Gain knob, with a Balance control
above. Other sources may display a single channel VU meter.
Confusion can sometimes arise because different calibration scales are common in various
audio realms and even for different device types and software. Typical analog mixers show levels on VU scales
indexed in dB VU, which places the nominal operating level at 0dB. In contrast, editing software and digital
devices commonly display levels in dBFS (Full Scale) indexing, with 0dBFS – the maximum signal that can be
recorded – at the top of the scale.
TriCaster's VU meters have user-configurable indexing, and default to showing analog inputs using a traditional
dB VU scale, and meters for digital sources calibrated in dB FS. The calibration shown for any individual meter
can be changed to suit a need or preference.
Click the label above the current scale to open a small menu offering three options as follows:

dBVU – most familiar to users of typical analog audio mixers

dBFS – dB 'Full Scale' – the digital standard; see notes under the heading.

dBu – based on a voltage of 0.775 VRMS (a shy scale rarely seen in public, supplied for completeness,
comparison, and the amusement of audiophiles)
Whatever scale you choose to use for your different VU meters, the key thing is to use Volume controls (and, for
the Mic input, the Gain control) to avoid over-modulation.
OUTPUT CONTROLS
Each of the audio sources discussed earlier provides its own contribution to TriCaster's audio output mix.
Settings in the output control panels in take effect downstream from all sources, further governing audio levels
sent to TriCaster's different output sections, including headphones and the Internet stream.
Figure 71
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