Martin Audio WLX - Manual (Page 28)

Polar variations with frequency
Whether particular frequency components add or subtract in the far field will depend on the loudspeaker
system spacing, the angular offset of the listener with respect to the centre line, and the wavelength.
The following polar responses show what happens when subwoofers are placed 8.6m apart and are driven in
unison at various frequencies:
100Hz
The polar plot shows the far field polar response of the two subwoofers when driven in phase with the same
100Hz signal. Subwoofer interaction causes irregular coverage either side of the centre line.
Response nulls (cancellations) occur at the sides because the spacing is an odd number of half-wavelengths
causing this frequency component to cancel in the far field.
80Hz
The above shows the same system at 80Hz.
At this frequency the central position remains well covered but the polar pattern has changed dramatically
around the sides. There are now strong lobes at the sides because the spacing is now an even number of half-
wavelengths at this particular frequency.
All material © 2007. Martin Audio Ltd. Subject to change without notice.