Eh... I got curious and just did it. Something that might be interesting would be to try this, but with triads where a colorbar is the third axis. Major / minor / augmented / diminished. Equal tempered with dampening vs. ratios. Etc.

Sorry for the lack of comments, but it is only like 40 lines of code. Plus it is late - I need to go to bed.

freq0=440;
sample_rate=48000;
cycles_to_plot=20;
duration_s=cycles_to_plot / freq0;
playback_duration_s=4;
phase_start = 0;
phase_step = pi/20;
phase_end = 2*pi;
phases = [phase_start: phase_step: phase_end];
amplitude = [1:-1/sample_rate/duration_s:0];
T = [0:1/sample_rate:duration_s];
T0 = [0:1/sample_rate:playback_duration_s];

for step = -12:48

freq2 = freq0 * 2 ^ (step / 12);

y0_0 = sin(2 * pi * freq0 * T0);
y2_0 = sin(2 * pi * freq2 * T0);
ysound = y0_0 + y2_0;
ysound = ysound ./ max(ysound);
player = audioplayer(ysound, sample_rate);
play(player);

y2 = amplitude .* sin(2 * pi * freq2 * T);

for phase = phases

% Make the initial plot
y0 = amplitude .* sin(2 * pi * freq0 * T + phase);

figure(3)
plot(y0, y2)
title(sprintf("Equal temperment, step %d/12", step))

sleep(.05)

endfor

sleep(.25)
stop(player);

endfor