Sample & Hold - Alesis Fusion Tutorial

ALESIS FUSION
More recently, many LFOs allow their rate to be controlled by some other controller. For
example, you could control LFO rate with velocity so that playing the keyboard hard will make
the LFO rate faster and vice versa ... playing softer yields a slightly slower LFO rate. Or it could
be controlled by another LFO or envelope generator a real-time controller (see below)...
endless possibilities
A few synths allow the 'shape' or symmetry of the LFO's waveforms to be altered as well for
even more control flexibility.
Fusion allows all of these and more but that's probably enough to be going on with for now!!!
Sample & Hold
This is another old module from the early days and it falls somewhere between being a
controller and a control processor.
Basically, it takes an incoming control signal, 'samples' it
according to the rate of the clock:
Here, with a slowly rising control input signal, we get a rising stepped output which, if
connected to pitch, would give us a kind of arpeggio effect. This is how they all relate:
The S&H processor takes ('samples') the level of the incoming signal at each clock pulse and
holds that value for the duration of the clock step whereupon it takes the value of the incoming
signal at the next clock pulse and holds that level and so on. So, in this case, the signal is low
at the first clock pulse so the output is held low until the next clock pulse. At that point, the
input signal is higher so that level is sampled and held. At the next pulse, the input is slightly
higher so that is held but at the next pulse, the input signal is lower as is the output level... etc..
9 This is not to be confused with 'sampling' audio signals for use in a sampler. Although the
principles are actually the same, the sample & hold unit's clock is operating at sub-audio
frequencies/rates and is thus for control purposes only.
Controllers
Sample & Hold
Input
Clock
ANALOG SYNTHESIS TUTORIAL
9
and produces a stepped output
Output
Rate
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