Final answer:
The question likely contains a typo since it refers to a Bourdon tube, which indicates pressure, but the provided info discusses musical instruments. Musical instruments can have symmetrical or anti-symmetrical boundary conditions affecting the frequency of sound they produce. The lengths of their tubes are varied in different ways, such as using finger holes or sliding bars.
Step-by-step explanation:
A Bourdon-tube instrument may be used to indicate pressure. However, it seems there is a mix-up in the question, as the information provided discusses musical instruments and not pressure measurement devices. To clarify the concept related to the provided information, when considering musical instruments, some can be modeled as tubes with symmetrical boundary conditions, such as being open at both ends or closed at both ends. Others have anti-symmetrical boundary conditions, with one end open and the other end closed. This modeling is essential to understand how these instruments produce sound.
Instruments like flutes and trombones change the length of their tubes to alter the sound frequency—flutes do this by opening and closing finger holes, and trombones use a sliding bar mechanism. Similarly, instruments such as tubas, which produce very low frequencies, have tubes that are coiled into loops due to the required length for such low pitches. Whether or not a musical instrument produces its fundamental frequency or an overtone depends on its vibration stimulation and shape.