What primarily affects spreading in acoustics?

The primary factor affecting spreading in acoustics is distance. As sound travels through a medium, such as water, it disperses or spreads out over a larger area, which is largely influenced by how far the sound has to travel.

With increasing distance, the intensity of the sound typically decreases due to the geometrical spreading of the wavefront. This phenomenon is often observed as sound waves diverge from a source, leading to a reduction in sound pressure levels at greater distances from the source.

Other factors, while they do influence acoustic properties, do not primarily dictate spreading. Temperature can affect the speed of sound in water, altering travel times, but it does not directly relate to the distribution of intensity over distance. Salinity also impacts sound speed but is not a primary factor in spreading itself. Wave frequency influences the propagation characteristics and behavior of sound, such as absorption and reflection, but does not primarily dictate how sound spreads through a medium in the same way distance does.