Audio Playback

PyTheory can synthesize and play tones and chords through your speakers using basic waveform synthesis.

Note

Audio playback requires PortAudio to be installed on your system. On macOS: brew install portaudio. On Ubuntu: apt install libportaudio2.

Playing a Tone

from pytheory import Tone, play

a4 = Tone.from_string("A4", system="western")
play(a4, t=1_000)   # Play A440 for 1 second

Playing a Chord

from pytheory import Chord, Tone, play

c_major = Chord(tones=[
    Tone.from_string("C4", system="western"),
    Tone.from_string("E4", system="western"),
    Tone.from_string("G4", system="western"),
])
play(c_major, t=2_000)  # Play for 2 seconds

Waveform Types

The waveform shape determines the timbre (tonal color) of the sound. Different waveforms contain different combinations of harmonics — integer multiples of the fundamental frequency.

• Sine wave — the purest tone. Contains only the fundamental frequency with no harmonics. Sounds smooth, clear, and “electronic.” This is the building block of all other waveforms (Fourier’s theorem).

• Sawtooth wave — contains all harmonics (both odd and even), each at amplitude 1/n. Sounds bright, buzzy, and aggressive. Named for its shape. Used extensively in additive synthesis and analog synthesizers.

• Triangle wave — contains only odd harmonics, each at amplitude 1/n². Sounds softer and more mellow than sawtooth — somewhere between sine and sawtooth. Often described as “woody” or “hollow.”

from pytheory import play, Synth, Tone

tone = Tone.from_string("C4", system="western")

play(tone, synth=Synth.SINE)      # Pure, clean
play(tone, synth=Synth.SAW)       # Bright, buzzy
play(tone, synth=Synth.TRIANGLE)  # Mellow, hollow

Temperaments

Hear the difference between tuning systems:

play(tone, temperament="equal")        # Modern standard (since ~1917)
play(tone, temperament="pythagorean")  # Pure fifths, wolf intervals
play(tone, temperament="meantone")     # Pure thirds, Renaissance sound

Try playing a C major chord in each temperament — you’ll hear subtle differences in the “color” of the major third. Equal temperament is a compromise; the other systems sacrifice some keys to make the good keys sound better.