How to convert an excel file (.csv) to a .wav format/any other audio format file?

Hi,

I have an excel file which has ~200k data samples stored in one column and I want to convert the data from that file into an audio file. But whenever I use the excel file, there is almost no sound. I want to play it at 40khz frequency.

I am just using this code:

clearvars

a=xlsread('w3.csv'); %read the xls table

figure,plot(a) %this is your signal

xlim([0 200704])

sound(a,40000) %play the signal

audiowrite('w3.wav',a,40000,'BitsPerSample',16);

Can someone help? Thanks.

[Voss]

Can you attach the file?

[Giggs B.]

I have attached the file.

Answer 1

[Scott MacKenzie]

I was able to play your audio data and save it as a .wav file. It's some sort of noise along with a dripping sound. But, I had to first rescale the data to fall between -1 and 1:

clearvars
a = xlsread('temp.csv'); % this is your w3.csv file
a = rescale(a, -1, 1); 
figure,plot(a) %this is your signal
xlim([0 200704])
sound(a,40000) %play the signal
audiowrite('w3.wav',a,40000,'BitsPerSample',16);

[Giggs B.]

Hi,

Yes! Thanks, it the sound of waterflow from a pipe. However, I wanted to know the logic behind that why would I need to convert it to -1 to +1. I also checked other ranges such as 0 to 1 or -5 to +5 or -10 to 10 and they all gave expected results.

Answer 2

[Peter Perkins]

This

should give a hint that xlsread is not the right way to go. In this case, you want to use readmatrix:

a = readmatrix("w3.csv")

[Giggs B.]

Hi Sir,

Thanks for the suggestion. However, when I use the same code and only change xlsread to readmatrix, I get the following error which does not appear when I am using xlsread. How do I fix this issue? Thanks.

Error in filtfilt>efiltfilt (line 114)
    validateattributes(x,{'double'},{'finite','nonempty'},'filtfilt');
Error in filtfilt (line 89)
        y=efiltfilt(b,a,x);
Error in binarytowav (line 9)
y_h2 = filtfilt(sos, g, m);

Below is my code:

clearvars
n= readmatrix("3.csv"); %read the xls table
m = rescale(n, -1, 1, 'InputMin',2301,'InputMax',3642)+0.47; %same way but in same line

fs=40000;
[z,p,k] = ellip(4,1,40,2400/(fs/2),'high'); %z,p,k method
[sos,g] = zp2sos(z,p,k);
y_h2 = filtfilt(sos, g, m);

figure,plot(m) %this is your signal
ylim([-0.5 0.5])
xlim([0 200704])
xlabel('Time (sec)');
ylabel('Amplitude');
title('Stage1 PCB, waterflow: >3gpm'); 

AmplitudeWaterflow=sum(abs(y_h2)) 

x = gca;
tick_scale_factor = 1/40000;
ax.XTickLabel = ax.XTick * tick_scale_factor;

sound(m,40000) 

[Scott MacKenzie]

@Giggs B. You've got the wrong filename in your script. The file is "w3.csv", not "3.csv". Fix that typo and it should work fine.

[Giggs B.]

@Scott MacKenzie, Sorry for the confusion. Actually i have lots of files. I used the correct file for which I was checking, but that error is persistant. For ex. please check my image, I am checking file "5.csv" but same error. And when I run the same code while using xlsread, it works fine.

[Scott MacKenzie]

@Giggs B. Hmm, well I'm not sure then. In the code in my answer, if I change xlsread to readmatrix, it works fine.

This sounds like a fairly simple debugging problem. So, for you, it works with xlsread, but it doesn't work with readmatrix. So, try to use both:

n1 = xlsread('3.csv');
n2 = readmatrix('3.csv');

and have a look in n1 and n2 and see what the difference is. That's a good starting point.

[Giggs B.]

Oh I see, yes then that looks some problem on my end. I will try to figure it out, starting from where you suggested. Thanks!