A panel audio loudspeaker includes a panel and an actuator rigidly coupled to a surface of the panel. The actuator includes: a magnet assembly that includes a permanent magnet arranged within a cup, wherein an air gap exists between sidewalls of the cup and the permanent magnet; and a coil rigidly coupled to the panel, the coil including a length of an electrically conducing wire wound in a coil and extending along an axis. The coil includes a first region having a first winding density and a second region having a second winding density higher than the first winding density, the second region at least partially extending into the air gap of the magnet assembly.