Lesson 10 of 15

Open Pipe Harmonics

Open Cylindrical Pipe

A pipe open at both ends (flute, organ open pipe) has pressure antinodes at each end. The resonant frequencies follow the same formula as a string:

f_n = rac{nv}{2L}, quad n = 1, 2, 3, ldots

  • n — harmonic number
  • v=343v = 343 m/s (speed of sound in air)
  • L — pipe length (m)

All Harmonics Present

An open pipe supports all integer harmonics — the same as a string. This gives it a bright, rich timbre (flute, recorder, human vowels).

Changing Pitch

Halving the pipe length doubles the frequency — one octave up. This is why flutes are shorter than tubas.

nL=1 mL=0.5 m
1171.5000343.0000
2343.0000686.0000
3514.50001029.0000

Your Task

Implement openPipeMode(n, L) returning the nth resonant frequency (v=343v = 343 m/s).

Run the code to hear the fundamental and second harmonic of a 1-metre open pipe.

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Click "Run" to execute your code.