Location of one signal buried/hidden inside another

I have to find a signal x which is buried inside another signal y. The signal y might not have exact values of x, but an approximation. y is 39514758*1 samples long and x is 18637*1. The signal x represents a spoken recording that appears only once in y. I need to find x within y upto 25000 samples and then the location of x in y to 2.5 seconds.

I don't know how to proceed. I tried doing strfind() and findsignal which didn't work. I used correlation instead and found the maximum value. But I don't know how to get the indices. Can you please help me out?

Corr=normxcorr2(x,y);
M=max(Corr);
index=find(Corr==M);

Although this isn't working. Please help me out.

[Adam Danz]

You can use interp1 to interpolate the x signal to the same resolution as the y signal in order to have a 1:1 correspondance between the two signals.