A coaxial loudspeaker apparatus (10) comprising a first unit (20) being arranged to propagate sound in a first frequency range; a second unit comprising a first waveguide (30) arranged to propagate sound in a second frequency range that is higher than the first frequency range, and a second waveguide (60) arranged to move, during operation, relative to the first waveguide (30); wherein the second waveguide (60) extends substantially in prolongation of the first waveguide (30). The invention also extends to a loudspeaker (190) incorporating the coaxial loudspeaker apparatus (10).