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The frequency band that is stored by audio media such as CDs is a fairly wide range from 20
Hz to 20 kHz, and it is difficult for a single speaker to be able to play back all frequencies in
such a wide range.
Because of this, several speakers can be used, with different frequency bands (such as treble,
medium and bass) allotted to each speaker so that wide frequency ranges can be played
back. The "Crossover" function is used to allot the frequency ranges that are to be played back
by each speaker in accordance to the installed speaker units and the layout of the speakers, in
order to obtain the maximum level of performance from the speakers and to provide the most
stable frequency characteristics.
The crossover function includes a high-pass filter (HPF) for playing back treble sounds, and a
low-pass filter (LPF) for playing back bass sounds. In addition, the HPF and LPF are used in
combination in order to play back sounds in the mid range.
-3dB
Bass range
20Hz
For example, when adjusting the HPF, frequencies that are lower than the specified frequency
are progressively dampened, rather than simply not being played back at all. The "slope"
adjustment function is the function that is used to adjust these dampening characteristics.
The slope characteristics of a filter are such that with larger slope values (for example 12 dB/
oct), the slope becomes steeper, and so the amount of sound mixing in with neighboring
bands becomes less so that only the target band is played back. However, it also causes the
merging of sound between speakers to become poorer and can result in greater distortion.
● The crossover function is a filter that allocates specified frequency bands.
● A high-pass filter (HPF) is a filter that cuts out frequencies that are lower than the specified
frequency (bass range) and allows higher frequencies (treble range) to pass through.
● A low-pass filter (LPF) is a filter that cuts out frequencies that are higher than the specified
frequency (treble range) and allows lower frequencies (bass range) to pass through.
● The slope is the signal level at which frequencies that are one octave higher or one octave
lower are dampened.
The larger the slope value, the greater the slope. In addition, when "PASS" is selected, the
slope is eliminated (sound does not pass through the filters), so that the crossover function
has no effect.
About crossover
fc1(LPF)
fc2(HPF)
Mid range
fc3(LPF)
Treble range
20kHz
fc4(HPF)
fc*: Cut off frequency
137
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