Simulation of the chirp echo created in the staircases of Mesoamerican pyramids

chirp.m

clap = audioread('clap.wav');
fs = 96e3;      % sampling frequency
N = 40;         % steps
ssize = 0.15;   % step size
delay = ssize * 2 / 340;
samples = round(delay * fs);
stairs = zeros(samples * N + length(clap) + N, N);
for i = 1:N
    samples = samples + 1;
    indexes = (i-1)*samples+1 : length(clap)+(i-1)*samples;
    stairs(indexes, i) = clap;
end
stairs = sum(stairs, 2);
audioplayer(clap, fs).play();
audioplayer(stairs, fs).play();

figure;
ax1(1) = subplot(2, 2, 1);
plot((1:length(clap))/fs, clap);
ax2(1) = subplot(2, 2, 2);
periodogram(clap);
ax1(2) = subplot(2, 2, 3);
plot((1:length(stairs))/fs, stairs);
ax2(2) = subplot(2, 2, 4);
periodogram(stairs);
set(ax2, 'xscale', 'log');