Difference between revisions of "Matlabsoundofmusic" - Rhea

Revision as of 15:13, 24 November 2018

Matlab Sound of Music

Matlab can be used to create signals that can mimic the sound of a musical note, which can be used to play the tune of a song. Each note of a song is created by individual sin waves at a frequencies for each note. The following line of music has three different notes, C D and E.

Do re mi Music https://www.sheetmusicdirect.com/en-US/se/ID_No/179064/Product.aspx

Each of the three notes in this piece have their own unique frequency. C has a frequency about 261.63 Hz. D and E notes are created by multiplying the C note frequency by a factor to create a new note. For D the factor is 9/8 and for E the factor is 5/4.

A sine wave when played without an envelope would create a constant volume sound. However, when striking a piano key the sound is at first loud and then fades as time goes on. To replicate this effect in matlab, the sine wave can be multiplied by a negative exponential coefficient. The following code creates the song above in matlab.

function doremi()

x = 261.625565; %frequency of C

delta = 1/ 8126; %step used for note vectors

notelength = 1; %how long each note is played

%creates vectors for note length intervals

tquarter = 0 : delta : 0.25*notelength;

thalf = 0 : delta : 0.5*notelength;

tthreefour = 0 : delta : 0.75*notelength;

ttwice = 0 : delta : 2*notelength;

%creating the sin waves for each note in the song

do = exp((-1)*tthreefour*3).*sin(2 * pi * x * tthreefour);

ad = exp((-1)*tquarter*3).*sin(2 * pi * (9 * x / 8) * tquarter);

deer = exp((-1)*tthreefour*3).*sin(2 * pi * (5 * x / 4) * tthreefour);

ac = exp((-1)*tquarter*3).*sin(2 * pi * x * tquarter);

fe = exp((-1)*thalf*3).*sin(2 * pi * (5 * x / 4) * thalf);

male = exp((-1)*thalf*3).*sin(2 * pi * x * thalf);

deer2 = fe;

%concatenating song to one vector

song = [do, ad, deer, ac, fe, male, deer];

%plays song

sound(song, 1/delta)