An acoustic black hole doesn’t have a partucular position-it describes the geometry in which a fluid moves.

I am not sure if we can call ABH a black hole because they dont have singularity.

By the way, the horizon of ABH is where the speed of medium, say, water exceeds the speed of sound.

Stam Nicolis ABH basically affects the structure-born noise due to the wave speed reduction phenomenon in the solid. ABH effect on the air-born noise is a secondary effect.

For instance in the following paper the structure born noise is discussed (without involvement of fluid).

Article A parametric study of an acoustic black hole on a beam

Mojtaba Shahbazi Maybe our meaning of ABH is different than what is in your field.

The introduction part of the above paper says:

"when the edge of a beam or plate is tapered, over a distance comparable to or larger than the flexural wavelength, the flexural wave speed decreases as the beam or plate thickness decreases. This phenomenon was described by Mironov in 1988", which clearly addresses the wave inside the solid.

The acoustic black hole describes the whole geometry-an acoustic black hole ``in'' a geometry doesn’t exist; it doesn't make sense. That's the point. ``Acoustic'', by the way, does imply a fluid-in which the sonic=sound (acoustic=sonic) waves propagate. The fluid is the analog of the spacetime-along with the boundary conditions, that ensure the propagation properties.

The ``black hole'' part describes a property of the propagation of these waves.

However, in contrast to what happens with real black holes, in real spacetime, acoustic black holes aren't the result of any physical process, the analog of gravitational collapse of a star, whose result can be understood as an object in the spacetime the collapse occurred. Here the acoustic black hole, that describes the properties of the fluid, in which sound waves propagate, is the spacetime itself. The horizon it defines, which is a coordinate artifact, is a ``sound-like'' surface, not a space-like surface, that's why the acoustic black hole isn't ``somewhere''.