The Relative System Level and Analog Reference Level are options that are defined in the configuration. They combine to set the operating levels (analog and digital) for the system.
With Relative System Level (dBFS) you define the relative working point internally within the system. This value can be calculated with the formula "RSL = - digital headroom - 18" or "RSL = working point -18dB".
For example, the working point (0 dBr) for the ARD (German Broadcasters' Network) is at -9 dBFS. From this follows a Relative System Level (dBFS) of -27.
Note that the working point is important as dynamics and limiter modules refer to this value. When the threshold value is set to 0 dB, the absolute level equals the working point.
The table below shows the values required to comply with the DIN and SMPTE metering standards.
| DIN | SMPTE | EBU |
|---|
| ON-AIR Designer: Relative System Level (dBFS) | -27 | -38 | -36 |
| ON-AIR Designer: Analog Ref Level (dBu) | 15 | 24 | 24 |
| Operating Level: Analog | +6 dBu | + 4 dBu | 0 dBu |
| Operating Level: Digital | -9 dBFS | -20 dBFS | -18 dBFS |
The ON-AIR Designer options can be edited via the "System -> Definition -> Parameter = Meter" branch of the 'Tree Definition'.