diode

diode is a diode ladder lowpass filter, adapted from code by Will Pirkle. The filter design is very similar to the one used by the iconic TB303 bassline generator.

It has the following argument structure:

• input: the signal to be filtered
• freq: the cutoff frequency (in Hz)
• resonance: the resonance amount of the filter (0-1)

The following example shows diode being used to create a subtractive bass sound.

 # Note Sequence
 _seq "0 2 3 7" gen_vals
 # Create clock, duplicate, and feed into sequencer
 8 metro dup 0 _seq tseq
 # bias squence to be pitched at 2 octaves below middle C
 36 + 
 # portamento filter to add glissando, then convert to frequency
 0.01 port mtof
 # feed frequency into bandlimited sawtooth generator
 0.8 saw 
 # feed clock into envelope, and multiply with sawtooth signal
 swap 0.001 0.01 0.2 tenvx * 
 # use LFO to control cutoff frequency of diode
 0.1 1 sine 1000 8000 biscale
 # the rest of diode, with resonance cranked up
 0.9 diode