ALLEN
&
HEATH
46 AP10733_1_XONE:PX5 User Guide
The XONE:VCF Voltage Controlled Filter
A Voltage Controlled Filter is an audio filter where the cut-off frequency is altered by a DC control
voltage rather than a variable resistor. This produces a much wider operating range and more control
over the filter response to create unlimited combinations of tonal effect.
Filter Type Select
The filters are ‘state variable’. This means that they provide three simultaneous filter types: high-pass,
band-pass and low-pass. Three large illuminated switches select which type is active.
You can press any combination together to create different response types such as ‘notch’ and an
interesting ‘all-pass’ effect. The switches are ‘soft switched’ for live performance, meaning that the
audio signal is ramped between filter states to prevent audible clicks.
NOTE: the last selected XONE:VCF response and Channel FILTER assignments are saved when mains
power to the mixer is turned OFF.
The graphs below show typical effects on audio frequency response for the three filter types.
The range of sweep from low to high frequency is shown together with the effect of adjusting
RESONANCE (one frequency with several resonance settings shown).
The vertical scale shows the amount of cut or boost around the normal 0dB operating level.
The horizontal scale shows the change in frequency from low (bass) to high (treble
).
FILTER REFERENCE
10k
20
1kHz
100
20k
0dB
+5
+10
+15
+20
-5
-10
-15
-20
LO-PASS FILTER
LO
HI
BAND-PASS FILTER
LO
HI
10k
20
1kHz
100
20k
0dB
+5
+10
+15
+20
-5
-10
-15
-20
10k
20
1kHz
100
20k
0dB
+5
+10
+15
+20
-5
-10
-15
-20
HI-PASS FILTER
LO
HI
10k
20
1kHz
100
20k
0dB
+5
+10
+15
+20
-5
-10
-15
-20
LO-PASS FILTER
LO
HI
BAND-PASS FILTER
LO
HI
10k
20
1kHz
100
20k
0dB
+5
+10
+15
+20
-5
-10
-15
-20
10k
20
1kHz
100
20k
0dB
+5
+10
+15
+20
-5
-10
-15
-20
HI-PASS FILTER
LO
HI
10k
20
1kHz
100
20k
0dB
+5
+10
+15
+20
-5
-10
-15
-20
LO-PASS FILTER
LO
HI
BAND-PASS FILTER
LO
HI
10k
20
1kHz
100
20k
0dB
+5
+10
+15
+20
-5
-10
-15
-20
10k
20
1kHz
100
20k
0dB
+5
+10
+15
+20
-5
-10
-15
-20
HI-PASS FILTER
LO
HI