Operation Manual

MALSTRÖM SYNTHESIZER
129
Filter types
To select a filter type, either click the Mode button in the bottom left corner or click di-
rectly on the desired filter name so that it lights up in yellow:
D LP 12 (12 dB lowpass)
Lowpass filters let low frequencies through and cut off high frequencies. This filter
type has a roll-off curve of 12dB/Octave.
D BP 12 (12 dB bandpass)
Bandpass filters cut both high and low frequencies, leaving the frequency band in
between unaffected. Each slope in this filter type has a 12 dB/Octave roll-off.
D Comb + & Comb –
Comb filters are basically delays with very short delay times with adjustable feed-
back (in Reason controlled with the Resonance knob). A comb filter causes reso-
nating peaks at certain frequencies.
The difference between “+” and “–” is in the position of the peaks, in the spec-
trum. The main audible difference is that the “–”-version causes a bass cut.
The Resonance parameter in both cases controls the shape and size of the peaks.
D AM
AM (Amplitude Modulation) is often referred to as Ring Modulation. A Ring Modu-
lator works by multiplying two signals together. In the case of the Malström, the fil-
ter produces a sine wave which is multiplied with the signal from osc:A or osc:B.
Resonance controls the mix between the clean and modulated signals. The Ring
Modulated output will then contain added frequencies which are generated by the
sum of, and the difference between the two signals. This can be used for creating
complex, non-harmonic sounds.
Filter controls
Each filter contains the following four controls:
D Kbd (keyboard tracking)
By clicking this button so that it is lit, you activate keyboard tracking. If keyboard
tracking is activated, the frequency of the filter will change according to the notes
you play on your keyboard. That is, if you play notes higher up on the keyboard, the
filter frequency will increase and vice versa. If keyboard tracking is deactivated, the
filter frequency will remain at a fixed value regardless of where on the keyboard
you play.
D Env (envelope)
If you click on this button so that it is lit, the cutoff frequency (see below) will be
modulated by the filter envelope. If you leave this deactivated, the Filter Envelope
will have no effect.
D Freq (frequency)
The function of this parameter depends on which filter type you have selected:
With all filter types except AM, it is used for setting the cutoff frequency of the fil-
ter. In the case of the lowpass filter for example, the cutoff frequency determines
the limit above which high frequencies will be cut off. Frequencies below the cutoff
frequency will be allowed to pass through. The farther to the right you turn the
knob, the higher the cutoff frequency will be.
If you have selected AM as filter type, this will instead control the frequency of the
signal generated by the filter. The same control range applies though; the farther
to the right you turn the knob the higher the frequency will be.
D Res (resonance)
Again, the function of this parameter depends upon which filter type is selected:
If the selected filter is any other type than AM, it sets the filter characteristic, or
quality. For the lowpass filter for example, raising the filter Res value will emphasize
the frequencies around the set filter frequency. This generally produces a thinner
sound, but with a sharper, more pronounced filter frequency “sweep”. The higher
the filter Res value, the more resonant the sound becomes until it produces a whis-
tling or ringing sound. If you set a high value for the Res parameter and then vary
the filter frequency, this will produce a very distinct sweep, with the ringing sound
being very evident at certain frequencies.
In the case of the AM filter type though, this control instead regulates the balance
between the original signal and the signal resulting from amplitude modulation.
The farther to the right you turn the knob, the more dominant the AM signal will be.
Comb + Low Resonance Comb + High Resonance
Comb – Low Resonance Comb – High resonance