What's This Sound Musically? (Included Matlab, Requires Musical Knowledge)

[Batuhan88]

Hello I found a Matlab code here and modified it a bit.
It simply takes three signals with different frequencies (nots C G and E) and inputs these three signals into one signal at a 4th frequency.

  %% configure signal settings
 duration = 3;                % duration in seconds
 amplitude = 0.8;               % amplitude
 f1 = 523;                     % frequency in Hertz
 f2 = 659;
 f3 = 783;
 phi = 2*pi*0.5;                % phase offset, e.g.: 2*pi*0.25 = 1/4 cycle
 %% configure output settings
 fs = 1760;                    % sampling rate
 T = 1/fs;                      % sampling period
 t = 0:T:duration;              % time vector
 %% create the signal
 omega1 = 2*pi*f1;              % angular frequency in radians
 omega2 = 2*pi*f2;
 omega3 = 2*pi*f3;
 partial1 = cos(omega1*t + phi)*amplitude;      % sinusoidal partial 1
 partial2 = cos(omega2*t + phi)*amplitude;      % sinusoidal partial 2
 partial3 = cos(omega3*t + phi)*amplitude;      % sinusoidal partial 3
 signal = (partial1 + partial2 + partial3)/3;
 %signal = (partial1 );
 %% plot the signal
 plot(t, signal);
 xlabel('Time (seconds)');
 ylabel('Amplitude');
 title('Complex Signal');
 %% play the signal
 sound(signal, fs);
 %% save signal as stereo wave file
 stereo_signal = [x1; x1]';
 wavwrite(stereo_signal, fs, 'test.wav');

If i didn't get it wrong, this code envelopes f1 f2 f3 signals (that are C G & E notes respectively) at a frequency of 440 Hz which is the A note.

So what's that i am hearing? A note? C major chord? anything like that?


Also, fs value can't take anything lower than around 1000 Hz. Why is that?

 

[FvM]

Yes, C major chord.

 

[BradtheRad]

fs = 1760; % sampling rate

You may hear musical tones at this low a sample rate. However sample rates for audio are normally much greater than this. I heard the figure 8kHz for video streaming. CD quality is 44.1 kHz.