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CD3000XL OperatorÕs Manual Page 107
USING THE FILTER AND ENVELOPE GENERATORS
One of the inherent problems of sampling is that, because of memory limitations, it is usually
necessary to loop a sample. This often has the effect of reducing (or even removing!) the
sound’s natural dynamics making the sample more like a snapshot than a movie.
To overcome this, however, we can use the filters and the envelope generators to restore
some of those attributes.
By bringing the filter cutoff frequency down and using note-on velocity as a controller, you can
emulate the characteristics of most, if not all acoustic sounds where loud notes are brighter in
tone than quiet ones. Controlling the output of ENV2 using velocity and applying that to the
filter is another way of doing this. Furthermore, another natural property of sound is that during
a note, the tonal quality changes. We can use envelopes and low frequency oscillators to
restore some of those qualities. Usually, the filter will use the multi-stage ENV2 as its controller
because tonal changes are usually more complex than amplitude changes in acoustic sounds.
This envelope can also be used to imitate such things as brass growls - to actually sample a
brass growl would not only take up memory but would speed up and slow down as you play it
across the keyboard. ENV2 could be applied to an ordinary brass sample and set so that Rate 3
swells back up from a low Level 2 to not only recreate this effect but also to keep the swell at a
constant rate across the keyboard. Pressure may also be used for the same effect although
you would be controlling the growl - this may be preferable to the ‘automated’ quality a preset
envelope rate would have.
Of course, once you are in the realm of sampling synth waveforms and processing them
through the filter, you are in different territory but anyone who has used an analogue synth will
feel instantly at home with the CD3000XL’s filter and envelope section. The only difference
here, however, is that instead of relying on a handful of waveforms, any sampled sound may be
used as the source. It is here that the modulation possibilities can be used to good effect in the
creation of new sounds (and the recreation of a few classic old synth sounds too!)
Having the filters, envelope generators and comprehensive modulation facilities in the
CD3000XL means that instead of having to sample an entire synth sound, you can simply
sample the ‘raw’ waveforms from the synth and apply all the other synth processing in the
CD3000XL. There are several ways this can be done - you could either sample multiple
detuned oscillators or you could sample individual oscillators and then layer them in the
CD3000XL. This might be preferable in a way as single waveforms can easily be looped and
take up virtually no memory space (*). With digital synths, you can take the basic waveform
material and build up a huge array of waveforms to use as the basis of your synth sounds.
* NOTE: Sampled waveforms do not detune in quite the same way as analogue synths. On
analogue synths, there are all kinds of pleasant distortion artefacts that give the sound
character - in some cases it is best to sample that distortion. Note also that sampled waveforms
transposed up and down the whole range of the keyboard do not sound quite the same as ‘the
real thing’ so it is probably best to multi-sample these for best results.