bore

The term "bore" can refer to a hole or the inner surface of a hollow cylindrical object, such as a gun barrel or engine cylinder. In the context of wind instruments, the bore's configuration significantly impacts the sound produced.12

Musical instruments with cylindrical or conical bores can create resonant frequencies that are harmonics of the fundamental pitch. However, bores that flare more rapidly than a cone produce nonharmonic overtones, resulting in harsh tones rather than pleasant musical sounds. This is why most Western musical instruments developed over the last millennium feature either cylindrical or conical bores. A flared bell is often added to the end of an instrument to improve sound radiation by reducing impedance mismatch.2

The bore shape influences which harmonics are present in an instrument's sound. For example, instruments like the flute, recorder, and violin, which function acoustically as open tubes, tend to produce all harmonics. In contrast, the clarinet, acting as a closed tube, emphasizes odd harmonics. Instruments like the trumpet and cornet, with cylindrical or conical bores respectively, can produce all harmonics due to the addition of a mouthpiece and bell.2