Second-Order Linkwitz-Riley Crossover

This 12 dB per octave crossover is designed to solve the problem of centering the main lobe of the forward radiation pattern of a two-way speaker system.

This crossover is unusual in that each filter is down 6 dB at crossover and that the two drivers are actually "in phase" at all frequencies when the drivers are wired in opposite polarity. That is, even though the filters have their own characteristic phase responses the phase difference between the two output signals is the same at all frequencies. As a result, each filter section has the same group delay.

This crossover is recommended over the 2nd order Butterworth type due to its accurate summed frequency response and forward pointing main lobe.

Inverted polarity is required for one of the drivers.
Second-Order Low Pass Filter Bandpass Filter Second-Order High Pass Filter
C1 = .0796 / ( Z x f )        C2 = .0796 / ( Z x f )
L1 = (.3183 x Z ) / f        L2 = (.3183 x Z ) / f

For optimal filter operation it is important to use the impedance (Z) of the loudspeaker at the cut-off frequency.
The DC resistance is NOT optimal for crossover filters!
If you don't know the loudspeaker impedance at Crossover frequency use the DC resistance of the loudspeaker,

How to measure Loudspeaker Impedance

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