How to generate sound in Matlab?

I want to generate sound for my sine wave but the sound did not come out. Is there something wrong with my code? Really need help, thanks.

fsampling = 1000;
f1 = 20;
f2 = 100;
f3 = 300;
fn1 = 150;
fn2 = 200;

fn1_normfreq = fn1/(fsampling/2);
fn2_normfreq = fn2/(fsampling/2);

x1 = cos(2*pi*f1*[0:1/fsampling:1.23]);
x2 = cos(2*pi*f2*[0:1/fsampling:1.23]);
x3 = cos(2*pi*f3*[0:1/fsampling:1.23]);
x = x1 + x2 + x3;
x(end) = [];
[b,a] = butter(2,[fn1_normfreq fn2_normfreq],'bandpass');
filtered_noise = filter(b,a,randn(1, length(x)*2));
y = (x + 0.5*filtered_noise(500:500+length(x)-1))/length(x)*2;
sound(y,fsampling)

Answer 1

[Chad Greene]

Use

soundsc(y,fsampling)

which scales the sound before playing it.

[Chad Greene]

Another option is to perform the scaling yourself:

sound(y/max(y),fsampling)

[Nur Fauzira Saidin]

Okay it works! Thanks. But it is possible if I want it to play like about 5 seconds?

[Chad Greene]

You could repeat y as many times as you want. This plays y five times in a row:

y_five_times = repmat(y,1,5);
soundsc(y_five_times,fsampling)

To get y to play for a specified amount of time, you'll have to repeat y enough times to fill the desired length, then only play the number of samples necessary to meet the time requirement:

% Enter how long you want the signal to be in seconds: 
Desired_length = 7.5; 

% Number of samples necessary to make the sound the desired length:    
num_samples = round(Desired_length*fsampling); 

% Number of times y must be repeated: 
num_repeats = ceil(num_samples/length(y));

% Create a vector of y repeated as many times as necessary:  
y_long = repmat(y,1,num_repeats); 

% Clip y_long to be exactly the desired length: 
y_long_clipped = y_long(1:num_samples); 

% Play the sound: 
soundsc(y_long_clipped,fsampling)

Answer 2

[Image Analyst]

For what it's worth, I have attached a demo that creates a weird sound and plays it.