The Mixer on most models support four primary audio busses: MASTER and AUX 1-3. Each of these is represented by its own control group in the Audio Mixer output section, and regulates sound sent to physical connectors or to logical outputs.
Tip: SHIFT + double click Volume knobs to restore their default values (0dB).
Settings in all of the control groups in this section 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.
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 audible issues. Over-modulation that may not be apparent while listening during live production, may appear in recorded files. This is often true even when levels appear to be below the ceiling level (0dBFS, the maximum allowable digital level).
Note: When clipping has occurred, the label for the problem channel turns red briefly.
Due to this problem, 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.
You can apply level control to suit your own preference in this regard, using the separate Record (and Stream) level controls. For example, levels set at -20dBFS in the Record Configuration panel approximate typical professional practice. This has no impact on levels at the system’s audio outputs, but ensures clipping in recorded files is 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.
Note: The Audio Mixer also provides Compressor/Limiters for each input and output. These can also be invaluable in defeating clipping due to over-modulation.
Level controls for the stereo audio that accompanies Streaming outputs are provided in the Output Configuration panel.