import random

import audiocore

import synthio

from ulab import numpy as np

import adafruit_wave as wave

h = np.array(

[

-0.001229734800309099,

-0.008235561806605458,

-0.015082497016061390,

-0.020940136918319988,

-0.024981800822463429,

-0.026464233332370746,

-0.024803890156806906,

-0.019642276775473012,

-0.010893620860173042,

0.001230341899766145,

0.016221637398855598,

0.033304135659230648,

0.051486665261155681,

0.069636961761409016,

0.086570197432542767,

0.101144354207918147,

0.112353938422488253,

0.119413577288191297,

0.121823886314051028,

0.119413577288191297,

0.112353938422488253,

0.101144354207918147,

0.086570197432542767,

0.069636961761409016,

0.051486665261155681,

0.033304135659230648,

0.016221637398855598,

0.001230341899766145,

-0.010893620860173042,

-0.019642276775473012,

-0.024803890156806906,

-0.026464233332370746,

-0.024981800822463429,

-0.020940136918319988,

-0.015082497016061390,

-0.008235561806605458,

-0.001229734800309099,

]

)

filter_coeffs = np.array(h[::-1] * 32768, dtype=np.int16)

def randf(lo, hi):

return random.random() * (hi - lo) + lo

SAMPLE_SIZE = 1024

VOLUME = 14700

sine = np.array(

np.sin(np.linspace(0, 2 * np.pi, SAMPLE_SIZE, endpoint=False)) * VOLUME, dtype=np.int16

)

square = np.array([24000] * (SAMPLE_SIZE // 2) + [-24000] * (SAMPLE_SIZE // 2), dtype=np.int16)

noise = np.array(

[random.randint(-32768, 32767) for i in range(SAMPLE_SIZE)],

dtype=np.int16,

)

bend_in = np.linspace(32767, 0, num=SAMPLE_SIZE, endpoint=True, dtype=np.int16)

envelope = synthio.Envelope(

attack_time=0.1, decay_time=0.05, release_time=0.2, attack_level=1, sustain_level=0.8

)

instant = synthio.Envelope(

attack_time=0, decay_time=0, release_time=0, attack_level=1, sustain_level=1

)

synth = synthio.Synthesizer(

sample_rate=48000, envelope=None, filter=filter_coeffs, channel_count=2

)

def synthesize(synth):

print(

"""you can use arbitrary waveforms, including ones calculated on the fly or read from wave files (up to 1024 points)"""

)

waveform = np.zeros(SAMPLE_SIZE, dtype=np.int16)

chord = [

synthio.Note(synthio.midi_to_hz(n), waveform=waveform, envelope=envelope)

for n in (60, 64, 67, 70)

]

synth.press(chord)

for i in range(256):

ctrl = i / 255

waveform[:] = np.array(square * (1 - ctrl) + sine * ctrl, dtype=np.int16)

yield 4

def synthesize2(synth):

print("""Envelope controls how notes fade in or out""")

chord = [

synthio.Note(synthio.midi_to_hz(n), waveform=sine, envelope=instant)

for n in (60, 64, 67, 70)

]

for i in range(4):

for c in chord:

synth.release_all_then_press((c,))

yield 24

synth.release_all()

chord = [

synthio.Note(synthio.midi_to_hz(n), waveform=sine, envelope=envelope)

for n in (60, 64, 67, 70)

]

for i in range(4):

for c in chord:

old = (c,)

synth.release_all_then_press((c,))

yield 24

def synthesize3(synth):

print("""A noise waveform creates percussive sounds""")

env = synthio.Envelope(

attack_time=0,

decay_time=0.2,

sustain_level=0,

)

notes = [

synthio.Note(

frequency=synthio.midi_to_hz(1 + i),

waveform=noise,

envelope=env,

)

for i in range(12)

]

random.seed(9)

for _ in range(16):

n = random.choice(notes)

d = random.randint(30, 60)

synth.press((n,))

yield d

def synthesize4(synth):

print("""Tremolo varies the note volume within a range at a low frequency""")

chord = [

synthio.Note(synthio.midi_to_hz(n), waveform=sine, envelope=None) for n in (60, 64, 67, 70)

]

synth.press(chord)

for i in range(16):

for c in chord:

d = i / 50

c.amplitude = synthio.LFO(scale=d / 2, offset=1 - d, rate=(i + 1) / 4, waveform=sine)

yield 48

yield 36

def synthesize5(synth):

print("""You can add vibrato or frequency sweep to notes""")

chord = [synthio.Note(synthio.midi_to_hz(n), waveform=sine) for n in (60, 64, 67, 70)]

synth.press(chord)

for i in range(16):

for c in chord:

c.bend = synthio.LFO(scale=1 / 24, rate=(i + 1) / 2, waveform=sine)

yield 24

synth.release_all()

yield 100

for c in chord:

synth.release_all()

c.bend = synthio.LFO(scale=randf(-1, 1), rate=1 / 2, waveform=bend_in)

synth.press(chord)

yield 320

def synthesize6(synth):

print("""Ring modulation multiplies two waveforms together to create rich sounds""")

chord = [

synthio.Note(synthio.midi_to_hz(n), waveform=square, ring_waveform=sine, envelope=envelope)

for n in (60,)

]

synth.press(chord)

yield 200

random.seed(75)

for _ in range(3):

synth.release_all()

yield 36

for note in chord:

note.ring_frequency = note.frequency * (random.random() * 35 / 1200 + 8)

synth.press(chord)

yield 200

def synthesize7(synth):

print("""FIR filtering can reproduce low, high, notch and band filters""")

chord = [

synthio.Note(synthio.midi_to_hz(n), waveform=square, filter=False)

for n in (60, 64, 67, 70)

]

for i in range(4):

for c in chord:

synth.release_all_then_press((c,))

yield 24

synth.release_all()

for note in chord:

note.filter = True

for i in range(4):

for c in chord:

synth.release_all_then_press((c,))

yield 24

def synthesize8(synth):

print("""Notes can be panned between channels""")

chord = [

synthio.Note(synthio.midi_to_hz(n), waveform=square, envelope=envelope)

for n in (60, 64, 67, 70)

]

synth.press(chord)

for p in range(-10, 11, 1):

for note in chord:

note.panning = p / 10

yield 36

def delay(synth):

synth.release_all()

yield 200

def chain(*args):

for a in args:

yield from a

# sox -r 48000 -e signed -b 16 -c 1 tune.raw tune.wav

with wave.open("demo.wav", "w") as f:

f.setnchannels(2)

f.setsampwidth(2)

f.setframerate(48000)

import array

for n in chain(

synthesize(synth),

delay(synth),

synthesize2(synth),

delay(synth),

synthesize3(synth),

delay(synth),

synthesize4(synth),

delay(synth),

synthesize5(synth),

delay(synth),

synthesize6(synth),

delay(synth),

synthesize7(synth),

delay(synth),

synthesize8(synth),

):

for i in range(n):

result, data = audiocore.get_buffer(synth)

f.writeframes(data)