matlab - Transform note to pitch and get the audio signal -

there pitch , duration , sample rate fs "pitch" vector of note pitch in semitones (with 0 indicating silence), "duration" vector of note duration in seconds, "fs" sample rate of output wave signals playback.

pitch=   [55 55 55 55 57 55 0 57 60 0 ]; duration=[23 23 23 23 23 35 9 23 69 18 ]/64; fs=16000; 

i want use above info return audio signal in matlab. can teach me?

thx

this requires thought , might take time write down before working.

personally, i'd split task multiple functions in mind involve:

1. semitone frequency 2. time sample number 3. frequency , sample number output waveform 

and if possible should add array involves level further progress later on/ helps simplify problem stages.

as im not sure semitone scaling using have confirm need sort of converter/look table (formulas according physics of music website):

 function [frequency] = semitone2frequency(semitone)      %your input how many semitones above middle c note      frequency = 440*((2^(1/12))^semitone); % 440 hz middle c  end 

this based on equal tempered scale. know frequency of notes generate sound, wait theres more....

now can calculate time of each sound in samples writing function...

function [nsamples] = time2samples(time, fs)     dt = 1/fs;     nsamples = time*dt; end 

now have both of these values can generate audio signal!

frequency = semitone2frequency(55); %55 semitones above middle c nsamples = time2samples(2,16000); %how many samples need play 2 seconds  %generate time array 0 how long want sound time = 0:1:nsamples;  %starts @ 0 increases 1 sample each time until 2 seconds worth of samples  %create output waveform! outputaudio = sin(2*pi*frequency.*time); 

this create array play sound note 55 semitones greater middle c (not sure note is) 2 seconds. listen using:

sound(outputaudio, 16000); 

you can build on create multiple sounds 1 after other (i recommend creating 1 master function lets pass arrays in , outputs 1 audio waveform), should enough create semitones given durations!

p.s. make level 0 @ time multiply outputaudio variable 0

outputaudio = outputaudio.*0; %the . in .* important! 

or further control multiply level between 0 , 1 complete volume control.

i hope enough! luck.