Cut a .wav audiofile to 30 sec by different data lenght

Hello,

I found lot of answers, how to cut last 10 sec, oder first 2 sec.

But I do a opposite - I have multiple of .wav-Files 35,36,31,...sec long

I want just to "reshape" a files and have first 30sec.

How it is possible?

I tryed:

 [y,fs] = audioread(filename);
filename = '20200605_004200.wav';
y(:,30*fs:end) = [];
wavFileName = '20200605_004200.wav';
audiowrite(wavFileName, y,fs);

But it does not working =)

Thank you in advise!

[Nik Rocky]

Or better to cut from t1 to t2