Open air columns produce harmonics for all harmonic numbers because they have antinodes at the open end. Closed air columns only produce odd harmonics because they have nodes at the closed end. The document also provides the equations that relate the harmonic number, wavelength, and length of the air column.

1. Open Air Columns
Antinodes  Open End
Occurs for all harmonics: 1, 2, 3, 4, 5 …
Closed Air Columns
Nodes  Closed End
Only occurs with odd harmonics: 1, 3, 5 …
4
n
L
n
λ =2
n
L
n
λ =
2
4
1
2
L
L
λ
λ
=
=
4
4
2
2
L
L
λ
λ
=
=
6
4
3
2
L
L
λ
λ
=
=
1
4
Lλ=
3
4
Lλ=
5
4
Lλ=
n is the harmonic #

2. Open Air Columns
Antinodes  Open End
Occurs for all harmonics: 1, 2, 3, 4, 5 …
Closed Air Columns
Nodes  Closed End
Only occurs with odd harmonics: 1, 3, 5 …
n is the harmonic #

3. Musical Notes & Frequencies
(Divide your frequency by 2 to raise it up an octave.)
C4 262
D 294
E 330
F 349
F#
/Gb
367
G 392
A 440
A#
/Bb
466
B 494
C5 523

5. Musical Notes & Frequencies
C4 261.63
D 293.66
E 329.63
F 349.23
F#
/Gb
369.99
G 392.00
A 440.00
A#
/Bb
466.16
B 493.88
C5 523.25

6. Musical Notes & Frequencies
C4 261.63
D 293.66
E 329.63
F 349.23
F#
/Gb
369.99
G 392.00
A 440.00
A#
/Bb
466.16
B 493.88
C5 523.25