- Since a closed-end tube can support only odd harmonics, the
next higher harmonic frequency (the first overtone) is the third
harmonic, f 3 , which is 3f 1 = 3(343 Hz) = 1,029 Hz. - For an opened-end tube, the harmonic frequencies obey the
equation fn = nv/(2L). The fundamental corresponds to n = 1, so
Since an opened-end tube can support any harmonic, the first
overtone would be the second harmonic, f 2 = 2f 1 = 2(343 Hz)
= 686 Hz.