How to add multiplicative noise to audio?

Hello everyone, I want to add multiplicative noise on top of the sounds. There is an example in the link attached to the picture. Can I add this code to my audio file in the same way?

J = imnoise(I,'speckle')

adds multiplicative noise using the equation J = I+n*I, where n is uniformly distributed random noise with mean 0 and variance 0.05.

Answer 1

[Jan]

According to the name "multiplicative noise" I'd expect this to work also:

t         = linspace(0, 5, 5 * 1000);
yourSound = sin(2 * pi * 8000 * t);
noise     = randn(size(t)) * 0.05;
result    = yourSound .* (1 + noise);

[studentmatlaber]

First of all, thank you very much for your answer. How do we know there is multiplicative noise here? my sound is available as a .wav file. For example, I downloaded the car noise from the internet as a .m file and added it to my sound file as follows.

randind = randi(numel(noise) - numel(audio),[1 1]);
noiseSegment = noise(randind : randind + numel(audio) - 1);

[Jan]

I do not understand, what this means: "How do we know there is multiplicative noise here?" The code I've posted creates multiplicative noise explicitly. So we know this, because we did this on purpose.

Additive noise means: output = signal + noise

Multiplicative noise means: output = signal * (1 + noise)

[studentmatlaber]

ı was confused. Now i understand. Thank you so much.

Answer 2

[Image Analyst]

Most image processing functions will also work with 1-D signals, as is the case with imnoise

v = 1 : 100;
vNoisy = imnoise(v, 'speckle', 2);

[studentmatlaber]

thank you so much.