Definition of Engineering Phrases
"A" "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",
"N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"

Crossover Network

An audio cross-over network is used inside a speaker to separate or filter audio signals of different frequencies to different speakers within a speaker cabinet designed to handle those frequencies. This particular crossover network uses two passive components for each filter.

Dual Speaker Crossover Network
Crossover Network

The low-pass filter is comprised of inductor L1 and capacitor C1, and is designed to pass low frequencies to a bass speaker or woofer. The series inductor [L1] tends to block high frequencies [XL increases], while passing low frequencies. At the same time the impedance of the parallel capacitor C1 is higher at lower frequencies. So at low frequencies the capacitor passes all the energy to the speaker, but as the frequency grows more energy is lost over the inductor, passing less energy to the speaker.

The high-pass filter is comprised of inductor L2 and capacitor C2, and is designed to pass high frequencies to a tweeter. The series capacitor C2 blocks or attenuates low frequencies from reaching the speaker, while the inductor L2 passes high frequencies to the speaker. Reducing the circuit could just leave the capacitor in circuit with the speaker forming a voltage divider.

Common values to use include 1mH for the inductors and 16uF for the capacitors. However almost any common value around those ranges will do depending on how fast, or slow, you want the crossover to take place between the speakers and the types of speaker used. Remember much of how a speaker sounds depends on the room it's placed in and of course the enclosure or cabinet that's used.

Among the speakers the editor uses include two 4-way, 6-speaker, KL-777A speakers from Kenwood covering the 25 - 22,000Hz audio frequency range. The KL777A has a tone selector which changes the sound from soft, normal, or clear [as stated on the knob]. The crossover frequencies are stated at 700Hz, 5000Hz and 10000Hz [Base, Midrange, High range]. The crossover network also states a 12dB / octive change. A set of KL555A have the crossover frequencies stated at 800Hz, 5000Hz, also with a tone selector.

Of course some home entertainment speakers, having only one speaker or two of the same type my not have a cross-over network at all. In any event because the preference is almost user defined, no values are used in the circuit schematic above.

Related Audio Circuits;
The pages provide schematic diagrams for both passive and active circuits, and in some cases a passive circuit that is also used with an active circuit [operational amplifier].
Audio Base Control, standard passive low frequency adjustment.
Treble Control standard passive high frequency adjustment.
Tone Control, for all in-one systems.
Midrange Adjustment Control, for more control.
Loudness Adjustment Circuit, for low volume bass.
Audio Amplifier Circuit, Operational Amplifier Schematic.
Audio Dual Channel Amplifier Circuit, Operational Amplifier Schematic.
Audio Mixer Circuit, Operational Amplifier Schematic.

PC motherboard

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