A french horn, one of the most beautiful sounding instruments in the orchestra,

Question

A french horn, one of the most beautiful sounding instruments in the orchestra, consists of about 3.32m (roughly 10.9 ft) of thin tubing, rolled into a spiral shape (although sizes do vary). The player blows into the mouthpiece, which can be treated as a closed end, and places his hand on the opposite end, which has a large flaring opening. In brass instruments, the fundamental note is not normally playable. Instead the first overtone is the lowest playable note. If the players hand keeps the large end open, what is the frequency of the lowest playable note? If the player now closes the large end with his hand, what is the frequency of the lowest playable note? (Note: the physics of the french horn is much more complex than is indicated here. The player's hand in the open end also changes the effective length of the tube, which than effects the frequency of the sound.)

Explanation / Answer

There will be a node at the mouthpiece and an anti-node at the bell, but it won't be the first anti-node since we are told that the lowest note is the first overtone. This means the lowest note has a wavelength of 4/3 l. The speed of sound at about body temperature is 331m/s + 0.6*37 m/s = 353 m/s What's new? c/lamda frequency = speed over wavelelength 353m/s/(4/3*3.56m) = 74 Hz This is a low note, but I think the French horn can play lower. B)Now we have a node at each end, but also a node in the middle, again it won't be the first anti-node since we are told that the lowest note is the first overtone. This means the lowest note has a wavelength of l. 353m/s/3.56m = 99 Hz

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.