I need to create a harmoniser in matlab (audio harmonisation)

I’m looking for some codes related to performing Harmonisation in matlab.

Answer 1

[albara]

Harmonization in the context of music typically refers to creating a chord progression, or harmonies, to accompany a melody. There isn't a standard Matlab function for music harmonization, but you could design a function that assigns chords to each note of the melody based on a set of rules. Here's a basic example where we assume the melody is a sequence of MIDI note numbers, and we harmonize in the key of C major.

function [chords] = harmonize(melody)

% Define the chords in the key of C major.

% Each chord is represented as a vector of MIDI note numbers.

C = [60, 64, 67]; % C major

Dm = [62, 65, 69]; % D minor

Em = [64, 67, 71]; % E minor

F = [65, 69, 72]; % F major

G = [67, 71, 74]; % G major

Am = [69, 72, 76]; % A minor

Bdim = [71, 74, 77]; % B diminished

chords = {};

for i = 1:length(melody)

note = melody(i);

switch note

case {60, 72} % C

chord = C;

case {62, 74} % D

chord = Dm;

case {64, 76} % E

chord = Em;

case {65, 77} % F

chord = F;

case {67, 79} % G

chord = G;

case {69, 81} % A

chord = Am;

case {71, 83} % B

chord = Bdim;

otherwise

error('Note %d is not in the key of C major.', note);

end

chords{i} = chord;

end

end

You can use this function by passing a melody as an argument. For example:

melody = [60, 62, 64, 65, 67, 69, 71, 72];

chords = harmonize(melody);

This will return chords, a cell array where each cell is a chord (represented as a vector of MIDI note numbers) that harmonizes with the corresponding note in the melody.

Remember, this is a very basic harmonization algorithm. Real music often contains more complex harmonies, and the choice of chords can depend on factors such as the melody's rhythm and the overall structure of the song.

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Thanks

[Anoushka]

What if I have an audio signal in c scale and I need to harmonise that?

[albara]

Harmonizing an audio signal is more complex because you first need to extract the melody, or sequence of notes, from the audio. This involves techniques such as pitch detection and note segmentation.

Once you have the melody, you can harmonize it using the method described in the previous response. Then, you would generate audio for the harmony and mix it with the original audio.

Here is a simple example of how you might approach this in Matlab. Note that this code requires the Audio Toolbox for reading and writing audio files, and the Signal Processing Toolbox for the pitch detection.

% Read the audio file.

[audioIn, fs] = audioread('melody.wav');

% Convert to mono if necessary.

if size(audioIn, 2) == 2

audioIn = mean(audioIn, 2);

end

% Extract the melody using pitch detection.

pitch = pitch(audioIn, fs);

% Convert pitches to MIDI note numbers.

midiNotes = 69 + 12 * log2(pitch / 440);

% Harmonize the melody.

chords = harmonize(midiNotes);

% Generate audio for the harmony.

harmony = zeros(size(audioIn));

for i = 1:length(chords)

if ~isempty(chords{i})

% Generate a chord by adding sine waves for each note.

for note = chords{i}

freq = 440 * 2^((note - 69) / 12);

harmony = harmony + sin(2 * pi * freq * (0:length(audioIn)-1)' / fs);

end

end

end

% Normalize the harmony to avoid clipping.

harmony = harmony / max(abs(harmony));

% Mix the harmony with the original audio.

mixedAudio = audioIn + harmony;

% Write the result to a new audio file.

audiowrite('harmonized.wav', mixedAudio, fs);

This code first reads an audio file and extracts the melody using the pitch function. It then harmonizes the melody using the harmonize function defined in the previous response. Next, it generates audio for the harmony by adding together sine waves for each note in the chord. Finally, it mixes the harmony with the original audio and writes the result to a new audio file.

This is a very basic example and may not give satisfactory results for complex music. A real-world application would likely require more advanced techniques for pitch detection, note segmentation, and harmony generation.

Important: There may be some mistakes in this answer Experts can tell if there are any mistakes and you might find better answer

[Anoushka]

can you share a sample audio i can use to run this code? because the signals I tried are not working with the function