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Audio Playback
==============
PyTheory can synthesize and play tones and chords through your speakers
using basic `waveform <https://en.wikipedia.org/wiki/Waveform>`_ synthesis.
.. note::
Audio playback requires `PortAudio <http://www.portaudio.com/>`_ to be
installed on your system. On macOS: ``brew install portaudio``.
On Ubuntu: ``apt install libportaudio2``.
Playing a Tone
--------------
.. code-block:: python
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
---------------
.. code-block:: python
from pytheory import Chord, play
# From a chord name
play(Chord.from_name("Am7"), t=2_000)
# From note names
play(Chord.from_tones("C", "E", "G"), t=2_000)
Waveform Types
--------------
The waveform shape determines the `timbre <https://en.wikipedia.org/wiki/Timbre>`_ (tonal color) of the sound.
Different waveforms contain different combinations of **harmonics**
integer multiples of the fundamental frequency.
- `Sine wave <https://en.wikipedia.org/wiki/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 <https://en.wikipedia.org/wiki/Fourier_series>`_).
- `Sawtooth wave <https://en.wikipedia.org/wiki/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 <https://en.wikipedia.org/wiki/Additive_synthesis>`_ and analog synthesizers.
- `Triangle wave <https://en.wikipedia.org/wiki/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."
.. code-block:: python
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:
.. code-block:: python
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.
Saving to WAV
-------------
Render tones or chords to a WAV file instead of playing them live.
This works even without speakers or PortAudio:
.. code-block:: python
from pytheory import save, Chord, Tone, Synth
# Save a single tone
save(Tone.from_string("A4"), "a440.wav", t=1_000)
# Save a chord
save(Chord.from_name("Am7"), "am7.wav", t=2_000)
# Choose waveform and temperament
save(Chord.from_name("C"), "c_triangle.wav",
synth=Synth.TRIANGLE, temperament="meantone", t=3_000)