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SECTION 15.8 OUTPUT AND PRIMARY BUS CONTROLS
As has been discussed (Section 15.7.2), TriCaster provides four primary audio busses – Master 1 and 2, and Aux 1 and 2. Each of these is represented by its own control group Audio Mixer’s output section, and regulates sound sent to physical connectors or to ‘logical outputs’.
Hint: Shift + double click Volume knobs to restore their default values (0dB).
Settings in all of the control groups in this section (Figure 263) take effect downstream from all audio sources, further modulating and processing audio sent to outputs as the Aux and Master mixes, for recording, and for Internet streaming.
Note: Record and Stream are logical outputs with their own control groups in the Audio Mixer’s output section. This allows them to be governed independently of other outputs that the same mixes may have been assigned to.
In digital audio systems, signal levels that exceed maximum values are uniformly assigned the maximum value, a condition known as “clipping”.
Clipping inevitably results in annoying audible issues. Worse, over-modulation that may not be apparent while listening during live production may nonetheless appear in recorded files. This is often true even when levels appear to be below the ceiling level (0dBFS, the maximum allowable digital level).
For this reason, digital audio system designs customarily allow substantial ‘headroom’ above the benchmark ‘alignment level’, making over-modulation much less likely. Often this allowance seems high to those familiar with analog audio systems; headroom levels between 18 and 24dB are not uncommon in professional digital audio realms.
TriCaster allows for any preference in this regard, by its provision of separate Record (and Stream) level controls discussed shortly. For example, dropping the Record slider to -20dBFS (our base recommendation, by the way) approximates typical professional practice. This has no impact on levels at TriCaster’s audio outputs, but all but ensures clipping in recorded files will be avoided.
Advanced users can thus record files conforming to regional standards or personal preference, substantially reduce the possibility of audio clipping in recorded files, and even adjust the level on the fly if necessary.
The main point to remember from all of this is that for digital audio recording “less is often more”. When it comes to levels, by all means go as high as necessary – but it’s equally practical to go no higher than necessary.
Hint: The Audio Mixer also provides Compressor/Limiters for each input and output. These can also be invaluable in defeating clipping due to over-modulation.
The Record control group provides dedicated level modulation over the audio recording chain applying to *most sources assigned to Output 1 and Output 2 in the Output Configuration panel.
Again, this control group has no effect whatsoever on audio sent to output connectors. Similarly, it does not impact audio levels in files which are configured (in Record Configuration) to capture anything other than Output 1 and 2.
* When Output 1 and 2 are assigned (in Output Configuration) to use audio directly from a designated TriCaster audio input (Input 1-8), the audio signal recorded is ‘pre-mixer’.
The Stream controls provide a method of independently adjusting levels and processing for (stereo) audio sent to the encoder when streaming is enabled.