A series of open toneholes creates what is known as a . This lattice acts as a high-pass filter.
If a wind instrument were just a solid pipe, it could only play the notes of its natural harmonic series. Toneholes are "leaks" intentionally placed along the tube to effectively shorten the air column, allowing for a chromatic scale. Effective Length vs. Physical Length A series of open toneholes creates what is known as a
While toneholes handle the notes, the bell handles the transition of the sound wave from the instrument into the room. A flared bell helps "match" the impedance of the air column to the outside air. In brass instruments, the bell shape is the primary factor in determining which harmonics are in tune; in woodwinds, the bell mostly affects the lowest few notes where all toneholes are closed. Toneholes are "leaks" intentionally placed along the tube