how to create speech waves with equal loudness in matlab ?

• Use the soundsc command:

 [y1,Fs1] = audioread('myRecord1.wav');
 [y2,Fs2] = audioread('myRecord2.wav');
  y1n = soundsc(y1,Fs1);
  y2n = soundsc(y2,Fs2);

• Use FFT to equalize the median dB:

 Pxx1 = abs(fft(y1));
 Pxx2 = abs(fft(y2));
 dB1 = median(10*log10(Pxx1(1:(end/2)).^2));
 dB2 = median(10*log10(Pxx2(1:(end/2)).^2));
 dB = [dB1 dB2];
 k = sqrt(10.^((max(dB)-dB)/10));
 y1n = k(1)*y1;
 y2n = k(2)*y2;