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)