What about parameters that need two measurements (impulse responses) to be computed?

Some parameters need two impulse responses to be computed. The number and type of microphones to be used is set from Room Acoustics->Calculation Options in the Microphone type(s) list box. If a type that uses two microphones is selected, it needs two measurements, a primary and a secondary. The primary measurement is taken from the upper plot and the secondary measurement is taken from the lower plot. These measurements are displayed in the Measurement Selection Toolbar, and can easily be changed from this toolbar as well.