  Loudspeaker rendering techniques that create phantom sound sources often
assume an equidistant loudspeaker layout. Typical home setups might not fulfill
this condition as loudspeakers deviate from canonical positions, thus requiring
a corresponding calibration. The standard approach is to compensate for delays
and to match the loudness of each loudspeaker at the listener's location. It
was found that a shift of the phantom image occurs when this calibration
procedure is applied and one of a pair of loudspeakers is significantly closer
to the listener than the other. In this paper, a novel approach to panning on
non-equidistant loudspeaker layouts is presented whereby the panning position
is governed by the direct sound and the perceived loudness is governed by the
full impulse response. Subjective listening tests are presented that validate
the approach and quantify the perceived effect of the compensation. In a setup
where the standard calibration leads to an average error of 10 degrees, the
proposed direct sound compensation largely returns the phantom source to its
intended position.
