BSS Audio FDS-318 Owner's Manual - Manual (Page 8)

8
Linkwitz-Riley Alignment
4.0 The Linkwitz-Riley advantage
There is an additional set of advantages exclusive to active crossovers made by
BSS, and other manufactures using the Linkwitz-Riley alignment (See Figure
4.1).
Fig 4.2 Radiation
Pattern Frequency
showing excellent on-
axis symmetry
Zero Phase difference at crossover: The phase difference between drivers
operating in adjacent frequency bands is close to zero degrees at the crossover
frequency.
'Phase alignment' in this manner prevents interactive effects (i.e.: High and
Low drivers 'fighting' each other) over the narrow band of frequencies around
the crossover point, which is where the units from two adjacent frequency
ranges are contributing near equal amounts of sound pressure.
More predictable sound dispersion: By providing in-phase summation at the
crossover point(s), the Linkwitz-Riley alignment provides for more coherent
sound dispersion - it provides on-axis symmetrical radiation patterns. (See
Figure 4.2).
'Invisible' slopes: The absence of electrical phase difference close to the
crossover frequency helps to make the steep -24dB/OCT slope effectively
inaudible. Response peaks and dips are negligible and inaudible given the
correct polarity ('phasing') of the speaker connections. The same is not true of
the shallower (-6, -12 or -18dB/OCT) rates or rolloff, in other crossovers.
Fig 4.1 Linkwitz-Riley
filters