A Practical Circuit Design
The above explained theory can be better understood through a small circuit design presented here. Readers may go on to build this circuit without hesitation as the idea of this passive crossover filter given below is practically feasible with excellent features. Let’s see how it responds and filters an applied audio frequency:
Referring to the figure, Low range filtration is mainly achieved by inductor L1 and capacitor C1. They result in a good roll over second order slope above 500 Hz.
L2 and C2 are basically responsible for low frequency rectifications.
The inclusion of R1 ensures an overall constant resistance at the network output even with the varying influence of L2/C2 and woofer impedance.
The mid range circuit is comprised of L3-C3 and L4-C2 which help in providing smooth roll offs at frequencies of 500Hz and 5KHz respectively. The roll off curves are at around 14dB per octave.
The tweeter section includes L5-C4 which effectively capture frequencies above 15KHz which is also the cross over point for this section. R5-R6 are arranged as attenuators for level matching at near 6dB to produce an acoustic flat response.
If you are intending to build the circuit, please dimension the wire gauge as per the input power so that the inductors used in the above explained three-way speaker crossovers don’t heat up.
Editor's Note: Several readers have pointed out that C1 in the diagram should be 100 mH, rather than 100 Ohm, as it is displayed now. You may wish to contact the author of the article about this issue on his blog: http://homemadecircuitsandschematics.blogspot.com/