4 distortion, Drive – FXpansion BFD2 Manual User Manual
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12:4 Distortion
Drive
BFD2’s Drive effect offers 4 distortion circuit models, useful for adding colour, grit or more
extreme distortion to your pristine drum sounds.
Mode
Diode
Diode clip circuits are found in countless guitar pedals and other distortion units. It gradually
drives the input throughout the amplitude range. It shapes the input signal’s amplitude as
shown in fig.1.
OTA (Operational Transconductance Amplifier)
This mode models the behaviour of an overdriven OTA chip. It shapes the input signal’s amplitude as shown in fig.2.
fig.1 : Diode
fig. : OTA
OpAmp (Operational amplifier)
This mode models the behaviour of an overdriven OpAmp chip. It shapes the input signal’s amplitude as shown in fig.3.
HalfRect (Half Rectifier)
This type of distortion allows through the top half of the input signal’s waveform. It shapes the input signal’s amplitude as shown
in fig.4.
fig. : OpAmp
fig. : HalfRect
Drive
This control sets the amount of distortion that takes place.
LP Freq & HP Freq
These crossover filters exist before the distortion stage to enable you to shape the tonal characteristics of the signal going into
the drive circuit. For example, you may want to distort the high end of a kick drum while leaving the deep low end unchanged.
The low-pass filters frequencies above the specified frequency. It has a slope of -6 dB per octave, and ranges from 1Hz to 100
Hz.
The high-pass filters frequencies above the specified frequency. It also has a slope of -6 dB per octave, and ranges from 1 kHz to
100 kHz.
These filters are crossover filters – the frequencies that are filtered out before the distortion stage are accessible via the Clean
control.