Specification of input impulse responses

The room acoustics calculations operate on a primary and an optional secondary impulse response. Most parameters are based on a single response, usually measured with an omni-directional microphone. These parameters are always calculated from the primary response. Some parameters, like lateral fractions and interaural crosscorrelations, are based on two responses. In these cases a secondary response must be provided as well, measured with an omni-directional or figure-of-8 microphone. The primary and secondary impulse responses must always have the same length and sampling frequency.

Specification of input responses to the room acoustics calculations is done by making the responses active in plot windows. The primary response is always taken as the active measurement in the upper plot, and the secondary response is taken as the active measurement in the lower plot. If only a single plot is displayed, its active measurement becomes the primary response. The secondary response is still the active measurement in the lower plot, and is specified in the Measurement Selection Toolbar (shown in the figure below) or in Plot->Select Plot Type(s) and Active Measurement. In any case, it is a good idea to check one of these to make sure that the correct impulse responses are specified before room acoustics calculation is initiated.

After a measurement the resulting response becomes the active measurement in the current plot window. It is therefore automatically chosen for room acoustics calculations. Measurement channel two can be automatically sent to the lower plot by checking the appropriate box in the bottom part of Measurement->Measurement Tasks.... If it is checked and a multi-channel measurement is performed, channel 1 will be plotted in the upper plot and channel 2 will be plotted in the lower plot. Make sure two plots are viewed, with only one plot channel two will not be displayed.

If several measurements are inserted using File->Insert…, the first measurement will be displayed in the upper plot, the second will be displayed in the lower plot, the third will be displayed in the upper plot, and the forth in the lower, and so on. Note that measurements may be selected in any order by clicking on the measurement files in the File->Insert… dialog.