Wrapping Bass: Implementation

February 3rd, 2012
music, octaveless
After thinking yesterday about octaveless notes I decided to write something to generate the tones I had in mind. Here they are as two-second mp3s:
Bb B C Db
A D
Ab Eb
G Gb F E
The code is on github. It uses portaudio so it should work cross platform if you want to compile it. The important parts of the code are:
#define sine(i,F) ((float) sin( (((double)(i)*(double)(F))/SAMPLE_RATE) * M_PI * 2. ))

float freq(float note)
{
  return 440*(pow(2, (note-69.0)/12));
}

float intensity(float note, int octave)
{
  float bass_n = fmod(note, 12);

  switch(octave) {
  case 0:
    return 0.00 + 0.01*bass_n;
  case 1:
    return 0.12 + 0.01*bass_n;
  case 2:
    return 0.24 + 0.01*bass_n;
  case 3:
    return 0.32 - 0.01*bass_n;
  case 4:
    return 0.22 - 0.01*bass_n;
  case 5:
    return 0.10 - 0.01*bass_n;
  }
  return 0; // never reached
}

float synth(float phase, float note) {
  return pow(2,(sine(phase, note)));
}

# A440 = 69, as in midi
# phase is constantly increasing, once per sample
#
float sample_val(float note, unsigned int phase)
{
  note = fmod(note, 12);

  return log2(synth(phase, freq(note + 12*0)) * intensity(note, 0) +
              synth(phase, freq(note + 12*1)) * intensity(note, 1) +
              synth(phase, freq(note + 12*2)) * intensity(note, 2) +
              synth(phase, freq(note + 12*3)) * intensity(note, 3) +
              synth(phase, freq(note + 12*4)) * intensity(note, 4) +
              synth(phase, freq(note + 12*5)) * intensity(note, 5));
}

# call sample_val as:
# for (int i = 0 ; i < 1000000 ; i++)
#   send_to_speaker(sample_val(69, i));
Referenced in: Footboard Bass

Comment via: google plus, facebook, r/WeAreTheMusicMakers, substack

Recent posts on blogs I like:

How to Make a Christmas Wreath

Yesterday, I made a Christmas wreath. Here's how to make one. First, find an evergreen tree near your house. Clip off a few branches from the tree. Try to have as many leaves or needles on the branches as possible. Next, bring them home. What I usu…

via Anna Wise's Blog Posts December 6, 2025

Live with Linch

A recording from Ozy Brennan and Linch's live video

via Thing of Things December 5, 2025

Against the Teapot Hold in Contra Dancing

The teapot hold is the most dangerous common contra dancing figure, so I’ve been avoiding it. The teapot hold, sometimes called a "courtesy turn hold,” requires one dancer to connect with their hand behind their back. When I realized I could avoid put…

via Emma Azelborn August 25, 2025

more     (via openring)