User`s manual
Page 22
Voyager XL User’s Manual - The Components
Page 23
Voyager XL User’s Manual - The Components
Filter Section Controls:
Cutoff:
The CUTOFF knob is the main lter control. This sets the cutoff frequency of both of the lters in the both
Dual Lowpass and Highpass/Lowpass mode.
In Dual Lowpass mode, the frequencies to the right (CW) of the indicator on the knob are the frequencies
that are ltered out. The frequencies to the left (CCW) of the indicator are the frequencies that are
allowed to pass through the lter. This is why as you turn the control clockwise the cutoff frequency
becomes higher and the sound becomes brighter. Of course to hear the effect of a lowpass lter it helps to
have a signal rich in harmonics which provides high frequencies to lter. A good example of a sound rich in
harmonics is a sawtooth waveform.
In Highpass/ Lowpass mode, the combination of highpass and lowpass lters forms a bandpass lter. The
CUTOFF control changes the center frequency of the passband.
Spacing:
The SPACING control is used to determine the difference between the cutoff frequencies of the two lters
in both Dual Lowpass mode and Highpass/ Lowpass mode. The numbers on the legend around the knob
refer to octaves. When the SPACING control is centered, the cutoff frequencies of the two lters are
identical and the lter sounds like a classic Moog Filter. Setting the SPACING control to +1 in Dual Lowpass
mode means that the right lter has a cutoff frequency equal to where the CUTOFF control knob is set,
and the left frequency has a cutoff frequency that is one octave higher than the right lter. This means when
the CUTOFF control is swept, two resonant peaks are heard, giving the lter a unique quality.
In Highpass/Lowpass mode, the SPACING control sets the difference between the cutoff frequencies by
shifting the highpass lter’s cutoff frequency up or down. When the SPACING control is fully clockwise, the
cutoff frequencies of the two lters are the same, making for a very narrow bandpass lter.
Resonance:
The RESONANCE control causes feedback in the lter circuit that adds harmonic emphasis at the cutoff
frequency. This control affects the lowpass lters in either lter mode, but not the highpass lter. When the
RESONANCE control is all the way down, the lowpass lters act as a tone control, rolling off high end as
the CUTOFF control is turned down. As the resonance increases, the lter begins to form a peak at the
cutoff frequency. Harmonic content within the frequency range of this resonant peak is emphasized, and the
sound takes on a vocal-like quality. As the RESONANCE control is turned up the peak increases in strength
until the control is set to 8 or higher, when the lter begins to self-oscillate – creating sine waves with the
same frequency as the cutoff frequency.
Keyboard Control Amount:
The KEYBOARD CONTROL AMOUNT knob allows the lter cutoff to follow the key played on the
Voyager keyboard (or the keyboard controlling the Voyager RME). A higher key will cause a higher cutoff
frequency. This allows a sound to retain its brightness as it is played higher on the keyboard.
Mode:
The lter MODE switch selects either the dual lowpass conguration (DUAL LP) or the highpass/lowpass
conguration (HP/LP).