Creating Overtones


Tutorial home




Flute players can change their embouchure and play in the flute’s higher vibrational modes.  This is how a flute can be played over several octaves, yet has only 12 toneholes.


Our model, unfortunately, can’t do that.  However, we can modify it so that it can.  If we place an additional delay in parallel with the existing one and tune it an octave higher, we can mix the outputs and make it sound like its being overblown an octave.


In the patch below, this idea is extended to four delays.  The first delay is tuned as before.  The second is tuned an octave higher, the third is tuned up an octave and a fifth, and the fourth is tuned up two octaves.  This corresponds to the notes in the harmonic series.


The “Overtone Select” knob chooses the overtone.





How it works


The outputs of the four delays are mixed together using the 8-input multiplexer.  Because the multiplexer’s XFade parameter is set to 100%, the inputs are crossfaded smoothly as the control input changes.  Routing each delay to two inputs instead of one creates wider and easier-to-find “stable” areas when playing the instrument.




A drawback


The overtones aren’t in tune, are they?  That is because they need tuning tables too, just like the fundamental.  We’re not going to pursue this subject further, because the next model, the flute, has a better way of creating overtones anyway.