Active Filters - Linkwitz Lab - Loudspeaker Design
Crossover filters of higher order than LR4 are probably not useful, because of an increasing peak in group delay around f 0. Top . 3 - 24 dB/oct Linkwitz-Riley crossover. The 24 dB/oct LR4 crossover filter provides outputs which are 360 degrees offset in phase at all frequencies.
