AN2=0.6; % All Pass Numerator constant Stage 2 level = 0.7; AD2=390; % All Pass Denuminator constant Stage 2 % All Pass stage 1 APden=[1,zeros(1,R5-1),AN1]; %All Pass Denumator AllPass1 = filter(APnum,APden,combfilt); num=[AN2,zeros(1,R6-1),1]; den=[1,zeros(1,R6-1),AN2]; % All Pass stage 2 % Add the echoes into the original signal and scale down level of echo REVERB = x + level * 3*AllPass2; soundsc(REVERB,Fs); subplot(325);plot(REVERB(1:30000)); xlabel('Time Variant'); ylabel('signal level'); title('Filtered Signal + REVERB'); XF = fft(REVERB,Fs);