Reed-driven woodwinds act as stopped pipes while flute-type reeds act as open pipes.

Evidence

Woodwind reed instruments make use of either a single or a double vibrat­ ing reed sound source which controls the flow of air from the player’s lungs to the instrument. The action of a vibrating reed at the end of a pipe is controlled as a function of the relative air pressure on either side of it in terms of when it opens and closes. It is therefore usually described as a pressure-controlled valve, and the reed end of the pipe acts as a stopped end (pressure antinode and velocity node—see Figure 4.18). Note that although the reed opens and closes such that airflow is not always zero, the reed opening is very much smaller than the pipe diameter elsewhere, making a stopped end reasonable. This is in direct contrast to the air reed in wood­ wind flue instruments such as the flute and recorder (see above), which, as a flow-controlled valve, provides a velocity antinode and a pressure node, and where the flue end of the pipe acts as an open end (see Figure 4.18). — David Howard, Jamie Angus, coustics and Psychoacoustics, 1236

Categorization

• DEFINE: Clearly distinguishes a pressure-controlled (stopped-end) valve from a flow-controlled (open-end) valve — a foundational acoustics mechanism useful for real instrument modeling.
• XREF: Connects to the Huygens/organ-pipe resonance material earlier in the book (Figure 4.18) and to how resonators shape any wind instrument. — connects to: Woodwind flue instruments act acoustically as pipes open at both ends — David Howard, Jamie Angus, coustics and Psychoacoustics, 1214; Reed pipes behave as stopped-end resonators, unlike open-ended flue pipes — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1205; Brass instruments are lip-driven pressure valves that behave acoustically like stopped pipes. (+4 more)

Broader Connections

• Reed pipes behave as stopped-end resonators, unlike open-ended flue pipes #corroborates (0.92) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1205
• Wind instruments divide into reed and non-reed sound-source types #expands (0.85) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1160
• Brass instruments are lip-driven pressure valves that behave acoustically like stopped pipes. #qualifies (0.75)
• Flute notes have a characteristic breathy onset with harmonics entering gradually after the fundamental #expands (0.72) — David Howard, Jamie Angus, coustics and Psychoacoustics, 1478
• Continuous-excitation instruments like flutes attack slowly while impulse-excited ones do not #expands (0.72) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 689