NFFT = 2^nextpow2(L);
y_buff = buffer(y,L_buff,overlap,'nodelay');
wnd = hanning(L_buff);

size_y_buff = size(y_buff);
num_fft = size_y_buff(2);

for j=1:num_fft
   y_fft = y_buff(:,j).*wnd;
   y_fft = [y_fft;zeros(L-L_buff,1)];
   Y_buff = fft(y_fft,NFFT)/(L-L_buff+sum(wnd));
   amp(:,j) = 2*abs(Y_buff(1:NFFT/2+1));
end
amp = sum(amp');