Automatic Tuning of Monophonic Digital Music Signals

Project source code for our ECE 529: Digital Signal Processing semester project

Team Members: Michael Bullock and Michael Inouye

Software:

To run, call monophonic_tuner.py with the following arguments:

required:

• -i input_file
  • give the file name of the monophonic .wav file to tune

optional:

• -o output_file
  • give the output .wav file name
• -fc key_frequency
  • give the frequency in Hz of the first note in the ionian mode to tune the music signal to. ex: for Gb aeolian, one would pass 440.0, the frequency in Hz for A ionian. the default is 261.63 for C ionian
• -fl lower_cutoff_frequency
  • give the lower cutoff frequency for the bp filter to be applied to music signal. the default is 40.0 Hz
• -fu upper_cutoff_frequency
  • give the upper cutoff frequency for the bp filter to be applied to music signal. the default is 5000.0 Hz
• -ss segment_size
  • give the segment size for tuning. note: segments must be large enough for the lowest frequency to be detectable. the default is 2048. note: must be smaller than 8000
• -so segment_overlap
  • give the overlap between segments to be tuned. the default is 64

Example Execution

python monophonic_tuner.py -i example0.wav -o example0_output.wav -fc 440 -fl 20 -fu 5000 -ss 2048 -so 64

Hardware:

To run, modify project_microcontroller.ino and deploy onto an Arduino Mega 2560

required:

const int operationMode = SAVE_AND_PLAY; // choose either SAVE_AND_PLAY or ON_THE_FLY

const int NUM_SAMPLES = 512; // total samples to collect per note

const int numNotes = 8; // number of notes to round to, inclding no notes

const int buzzerPin = 12; // GPIO for buzzer

const int detectPin = 2; // GPIO for incoming buzzer signal

const int noteDuration = 300; // 300ms note playback

const long int notes[numNotes] = {0, 262, 294, 329, 349, 392, 440, 494}; // note frequencies in major key

const char names[numNotes] = {'X', 'C', 'D', 'E', 'F', 'G', 'A', 'B'}; // note names to select