tparker48 / d_organ Goto Github PK

Several tasks in one.

• OSC1 and OSC2 each require a low-pass filter (LPF)

• The LPFs will read cutoff frequency and resonance as inputs

• OSC3 requires a band-pass filter (BPF)

• The BPF will accept cutoff frequency, resonance, and LFO rate as inputs.

• LFO rate corresponds to the rate of a dedicated SH LFO (Sample and Hold, Low Frequency Oscillator). The LFO amount is fixed

• OSC4 requires a high-pass filter (HPF)

• The only parameter is "shimmer" (might change this name later)

• "shimmer" is an abstract parameter that controls a bunch different thingsTBD)

If the onboard audio doesn't cut it (likely), a dedicated sound card will be required for high quality, seamless playback. Any pops, latency, artifacts, or unwanted distortions are unacceptable!

The crunch knob will control the amount of distortion that is applied to the signal.

• The method of distortion is (TBD)
• The distortion is applied just before the delay

write code for the pots:

• supports up to 36
• values updated in parallel with the audio processing
• provides linear or logarithmic scale values

The delay section has three parameters as input:
Time, Feedback, and Dry/Wet %

The oscillators are going to be challenging. They're actually closer to full blown samplers dedicated to a specific sound.

Each oscillator will have access to one unique audio file. It is the job of the oscillator to:

• receive the desired frequency
• receive the desired gain
• (CANCELLED)choose the audio file closest to the target frequency
• (CANCELLED) smoothly transition between different files with no audible "clicks"
• speed/slow the chosen sample to the exact target frequency
• interpolate when iterating by a non-integer through samples
• populate the audio buffer with gain taken into consideration

The ableton prototype needed a compressor to avoid peaking. This may be necessary and would be applied as a last step before the sound output.

Generic LFO class for all the modulation needs.
Specific LFO types will inherit from the generic class.
Sin Wave LFO, Sample and Hold LFO, Hybrid LFO.

The master filter is the most complex in terms of parameters.
Specs:

• Low Pass Filter (specifically, an imitation of the famous Moog Ladder filter)
• LPF has parameters Cutoff Frequency and Resonance
• For modulation, the LPF has a dedicated SH LFO, which takes modulation frequency and amount as inputs. The modulation is applied to the cutoff.

Write a bash script to be run on any raspberry pi. The script will handle compilation and setup for the synthesizer.

This includes things like:

• adding gpio.sh to startup
• enabling SPI
• configuring audio devices for output

dorgan won't do