Filter types

To select a filter type, either click the Mode button in the bottom left corner or click directly on the desired filter name so that it lights up in yellow:

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.

HP 12 (12 dB highpass)

Highpass filters are the exact opposite of lowpass filters, cutting off low frequencies and letting high frequencies through. This filter type also has a roll-off curve of 12 dB/Octave.

Comb + & Comb -

Comb filters are basically delays with very short delay times with adjustable feedback (in Reason controlled with the Resonance knob). A comb filter causes resonating peaks at certain frequencies.


The difference between "+" and "-" is in the position of the peaks, in the spectrum. 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.

AM

AM (Amplitude Modulation) is often referred to as Ring Modulation. A Ring Modulator works by multiplying two signals together. In the case of the Malström, the filter 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.