How to iterate and play sinewaves in succession..

Hey all,

Slowly getting there with my program but would like some advice on the best method to preform the sine wave generation. So far it works but all waves play at the same time and i want each one to play for 1 sec in turn. Obviously my code for this is so far clumsy and long so i'd need to iterate through something to reduce my code and to get it so do the desired thing..

Below is my full code, just so you can see where some of the data and variables come from:

prompt={'1st Note:','2nd Note:','3rd Note:','4th Note:','5th Note:','6th Note:','7th Note:'};
name='Enter Note Values (C-B)..';
defaultans={'C','D','E','F','G','A','B'};
answer=inputdlg(prompt,name,[1,50],defaultans);
% These three lines replace all of your loop and elseif statements:
V = 'CDEFGAB';
idx = cellfun(@(c)find(V==c),answer);
frq = [261.626,293.665,329.628,349.228,391.995,440.000,493.883];
out = frq(idx);

% GENERATE SINE WAVES..
%samples
N = T*Fs;
Fs = 44100;
%samples vector
tX1 = 0:1/Fs:1;
tX2 = 1:1/Fs:2;
tX3 = 2:1/Fs:3;
tX4 = 3:1/Fs:4;
tX5 = 4:1/Fs:5;
tX6 = 5:1/Fs:6;
tX7 = 6:1/Fs:7;

% CREATE SINE WAVES..
Sine1 = sin(2*pi*out(1)*tX1);
Sine2 = sin(2*pi*out(2)*tX2);
Sine3 = sin(2*pi*out(3)*tX3);
Sine4 = sin(2*pi*out(4)*tX4);
Sine5 = sin(2*pi*out(5)*tX5);
Sine6 = sin(2*pi*out(6)*tX6);
Sine7 = sin(2*pi*out(7)*tX7);

% PLAY SOUNDS..
soundsc(Sine1,Fs)
soundsc(Sine2,Fs)
soundsc(Sine3,Fs)
soundsc(Sine4,Fs)
soundsc(Sine5,Fs)
soundsc(Sine6,Fs)
soundsc(Sine7,Fs)

Thanks,

Paul..

[Edmund Paul Malinowski]

I've tried this as a loop but its not quite right:

% GENERATE SINE WAVES..
%samples
N = T*Fs;
Fs = 44100;
tXstart=0;
f = out(1);

for i = 1:7;
    tX = tXstart:1/Fs:tXstart+i;
    f = out(i+i);
    SineZ{i} = sin(2*pi*f*tX);
    soundsc(SineZ{i}, Fs); 
end

It plays some horrible sounds then some of them as expected but not the full 7 second loop as intended. I'm getting closer though haha

[N/A]

why doesnt this generates a graph of the wave?

[Star Strider]

@Maaz Rao —

Do you see a plot call in that code?

I don’t.

Answer 1

[Star Strider]

I didn’t run your code, but if you want to create an audioplayer object, you can use the playblocking function.

Otherwise, it’s likely easier to insert a pause(n) call (where ‘n’ is the number of seconds each tone lasts) after your soundsc call.

[Edmund Paul Malinowski]

Hey Star, cool thanks. I'll look into play and playblocking or even add the pause as you suggest. I'll let you know and tick this answer once i've got it sorted :)

[Star Strider]

My pleasure. I’ve used both methods in my code successfully.

[Edmund Paul Malinowski]

Star, I for speed i used the pause idea and with adapting some of my code as i spotted a few mistakes, it now works as i need it. Good shout, thanks :)

[Star Strider]

As always, my pleasure!

[Edmund Paul Malinowski]

I know this should be a new question but as its related I thought I'd throw it out there haha:

Using the code now as:

for i = 1:7;
    tX = 0:1/Fs:1;
    %tX = tXstart:1/Fs:tXstart+i;
    f = out(i);
    SineZ{i} = sin(2*pi*f*tX);
    soundsc(SineZ{i}, Fs);
    pause(1); 
end

This may sound dumb but how can i combine all the elements of SineZ into another variable so i can plot the entire 7 second sine melody?

I tried:

plot(tX,SineZ)

but it errors on the SineZ obviously. I want to do the same thing to tX.

I want to have something thats like when you:

[y,Fs] = audioread('some.wav');
plot(t,y)

but using my user created melody, not an audioread. So i can plot the entire melody in one graph

[Star Strider]

I took a few liberties with your code here to make it work:

frq = [261.626,293.665,329.628,349.228,391.995,440.000,493.883];
Fs = 44100;
T = 1;
for i = 1:7;
    tX = 0:1/Fs:1;
    %tX = tXstart:1/Fs:tXstart+i;
    f = frq(i);
    SineZ{i} = sin(2*pi*f*tX);
    soundsc(SineZ{i}, Fs);
    pause(1); 
end

SineZ_p = cell2mat(SineZ);                                  % Concatenate Vectors
t_p = linspace(0, length(SineZ_p), length(SineZ_p));        % Create Matching Time Vector
sound(SineZ_p, Fs);                                         % Check To Be Sure The Concatenation Worked

figure(1)
plot(t_p, SineZ_p)
grid

The figure is not very informative, since you’re plotting 308707 data.

The sound call after the t_p assignment is not necessary for the code, and can be deleted. I kept it in because it offers an alternative way of playing your entire ‘SineZ’ vector without having to use any pause calls.

[Edmund Paul Malinowski]

That's awesome. I need to work on the plots now properly but the main sound generation bit is done. Thanks so much for your help, Star :)

[Star Strider]

As always, my pleasure!

I learn a lot from solving problems here, so it’s a win for all.