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sound: Bach by Michala Petri

Standing waves

Higher harmonics for one loose end


If one end of the cord, say at x=, is a loose end, then at that position one must have an anti-node. Hence, 2A sin(k) must be maximum

2A sin(k) = ±2A


That can be achieved for

k = π/2, 3π/2, 5π/2, 7π/2, ...


With k=2π/λ and v=fλ, one arrives at

f = v/4, 3v/4, 5v/4, 7v/4, ...


The above formula describes the relation for the lengths of tubes and the tones produced, for wind instruments like a pipe organ, a trumpet or a saxophone.



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