The terms "sound bubble" and "sound vacuum" are not commonly used in the field of acoustics, and they do not have well-established definitions. However, based on the context and the general understanding of sound and vacuum, we can provide some interpretations:
Sound Bubble: A "sound bubble" could be conceptualized as an area or region where sound waves are somehow contained or localized. In this context, it might refer to a region with specific acoustic properties, such as sound insulation or a quiet zone. For example, an anechoic chamber is a specially designed room that absorbs sound waves, creating an environment with minimal reflections and reverberation. This chamber can be considered a "sound bubble" as it effectively isolates sound from the external environment.
Sound Vacuum: A "sound vacuum" could be interpreted as an area or region devoid of sound or with an extremely low sound level. In this sense, it might suggest a complete absence of sound waves. While it is not practically possible to achieve a perfect "sound vacuum" in the natural environment, certain environments, such as outer space or an isolated laboratory, can have extremely low sound levels due to the absence of a medium for sound propagation or minimal sound sources.
It's important to note that these terms may be used metaphorically or conceptually, and they do not have standard definitions in acoustics or physics.