ALM-018 - ‘MUM M8’
Introduction
‘MUM M8’ is an 8hp Eurorack low pass filter building on the filter design used in the
classic Akai S950 12 bit sampler with the addition of resonance, voltage control,
clipped saturation and a dedicated VCA.
The low pass filter gives the recognisable super smooth vacuum like tone sucking
sound which works magic on complex sources. The addition of clipped overdrive and
intentionally aggressive self oscillating resonance compliment the smooth filter core
by juxtaposing it into more wasp like territory with acidic squeals and a more gritty
sound.
Mum M8 features dual voltage control with attenuation (and inversion) of filter cut
off and voltage control of resonance together with dual audio inputs - one of which
includes a VCA to with the capability to aid overdriving signals into the filter core.
The filter core is a 6th Order Butterworth switched capacitor type design featuring
an analog core but controlled by a high speed digital clock. This produces the
characteristic smooth sounding filter but, as with the original S950, has a relatively
high minimum cut off as to avoid ‘clock bleed’ into the filter output from the digital
control. This minimum cut of point (and introduction of bleed if required) can be
controlled via trimmers on the rear of the module (see calibration chapter). It is not
unusual for there still to be some low level artefacts from the clock present,
particularly during filter sweeps - these add to the filters character.
The motivation for the module came from discussing filters in classic samplers
with the artist Jack Adams - aka Mumdance. Jack suggested investigating the S950’s
filter well known as for it use in classic use in early jungle and hardcore. From that
point onward Jack provided inspiration, help and feedback in the development of the
filter. Big up Mumdance.
!
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