Hollywood 24CX-2, 24CX-3, 24CX-4 owner manual dB per Octave Filter Curve

	5
	0
	-5
	-10
	-15
(dB)	-20
Gain
	-25
	-30
	-35
	-40
	-45
	380	500	620	740	860	980	1100	1220	1340	1460	1580	1700	1820	1940	2060	2180	2300	2420	2540	2660	2780

Frequency (Hz)

Figure 4 - 24 dB per Octave Filter Curve

To make a 2-way crossover, we feed the same signal into a high-pass filter and a low-pass filter with the same cutoff frequency. This is called the crossover frequency. The output of the high- pass filter is the high output of the crossover. The output of the low-pass filter is the low output of the crossover. The crossover frequency knob simultaneously adjusts the cutoff frequencies of both filters to vary the crossover frequency. Because the cutoff frequency of a filter is the point at which the output signal is 6 dB below the input signal (which means that it has half of the amplitude of the input signal), the crossover frequency is the frequency where half of the signal goes to the low speaker and half goes to the high speaker. Below the crossover frequency, progressively more signal is sent to the low speaker. Above the crossover frequency, progressively more signal is sent to the high speaker. Thus, there is a smooth transition between the low and high speakers. This is why we call it a crossover. To illustrate, Figure 5 shows the frequency response curves of both filters in a 24 dB per octave 2-way crossover at 1000 Hz.

	20
	0
	-20
	-40
(dB)	-60
Gain
	-80
	-100
	-120
	-140
	31	62	125	250	500	1000	2000	4000	8000	16000

Frequency (Hz)

Low Output High Output

Figure 5 - Crossover Frequency Response

© 2003 TDM Audio, Inc. Electronic Crossover Owner’s Manual Page 8