User specified reference level

If user specified reference level is used, yet another dialog box can be opened with the button User specified settings. In this dialog L_ref can be specified directly or calculated from reference measurements, all assuming calculation in octave bands are used.

Direct specification of L_ref is done in dB. This is useful in the case where the source and measurement equipment has been pre-measured in an anechoic room or otherwise, the reference level calculated, and the actual room measurement performed with exactly the same equipment and level settings. Alternatively known level changes can be used and corrected for. The calculation procedure described in the following subsection can be used to find reference levels for later use.