one-bit-instrument(7) Numm Tutorials one-bit-instrument(7)
NAME
one bit instrument - how to make a gnarly synth with numm-run
SYNOPSIS
numm-run FILE
DESCRIPTION
In this tutorial we will learn how to live-code a one-bit synthesizer controlled by mouse position. It is intended as a gentle introduc-
tion to development with numm-run.
To get started, create a text file with the following method stubs:
def audio_out(a):
pass
def video_out(a):
pass
Save the file as onebit.py, and then launch it with numm-run:
numm-run onebit.py
You should see a blank window appear. We will now make some sound and light by changing the value of a in the audio_out and video_out
functions:
def audio_out(a):
a[::100] = 2**15
def video_out(a):
a.flat[::100] = 255
Save the file, and you should see and hear the sketch update. This is using numpy's array-indexing to turn every hundredth audio sample
and pixel-color on. The audio sample rate is by default 44100Hz, so it produces a series of clicks that will be perceived as a 441Hz tone.
We can turn this into an instrument by connecting mouse motion to frequency:
period = 100
def audio_out(a):
a[::period] = 2**15
def video_out(a):
a.flat[::period] = 255
def mouse_in(type,px,py,button):
global period
period = px*1000
Finally, let's use the keyboard to record and jump to notes. The first time you press a key, it records the period, and subsequant depres-
sions play the saved period:
period = 100
record = {}
def audio_out(a):
a[::period] = 2**15
def video_out(a):
a.flat[::period] = 255
def mouse_in(type,px,py,button):
global period
period = px*1000
def keyboard_in(type,key):
global period
if record.has_key(key):
period = record[key]
elif record.has_key(key):
record[] = period
SEE ALSO
numm-run(1), numm.getting-started(7), numm.spectral-analysis(7)
numm February 2012 one-bit-instrument(7)