The Radiation of the Sound Source

As mentioned in section here and here, the main effects due to the directivity and orientation of the sound source can be reproduced by spectral corrections of the direct sound and of the signal that feeds the artificial reverberation algorithm. These corrections are interpreted as a modification of the acoustic quality perceived by the listener, which causes an update of the displayed values of the perceptual factors.

The control of these effects takes the following form in Spat_OPer:

• source power spectrum (as a "double shelving" curve),

• source directivity index (as a "double shelving" curve),

• angular orientation of the source.

As shown on figure here, there is a second mode in which these corrections are directly translated to low-level control parameters sent to the Source~ module. In this case, their effect on the global acoustic quality will not be taken into account by the perceptual interface (which also implies that they will not be considered in the automatic compensation procedure, described in the next section). However, the user may in some cases prefer this method if the equalization that can be realized with the direct and room filters in the Room~ module is considered too limited because it offers only three frequency bands and the transition frequencies are fixed by Spat_OPer (see also section).