If you hammer a piece of wood with termite galleries inside the sound will be hollow.
Termites in wall sound.
The gnawing and nibbling sometimes can only be detected with magnification e g.
The hollow sound heard when the wood is tapped.
However there are ways to detect their presence.
The pests use the vibrations caused by these movements to warn their colonies of danger.
When disturbed or threatened soldier termites create rattling noises by hitting their heads against the walls of tunnels.
By a stethoscope or a glass.
The loudest sound termites can make is called head banging.
There re many animals beside termites that can make noises in the walls.
Sound of termites can be described as tapping crackling and popping.
While the first two sounds are physically caused by termites in action the latter stems from hollow voids left in the wood by termites as they eat through your home.