Electronic device having a tuned resonance haptic actuation system

An electronic device, comprising:

• an enclosure;
• a display positioned with the enclosure and defining a front face of the electronic device;
• and
• a haptic actuator comprising:
• a housing comprising a wall;
• a movable mass positioned within the housing and configured to move relative to the housing to impart a force on the housing, thereby causing the haptic actuator to produce a haptic output that is part of a vibrational response of the haptic actuator;
• and
• a channel formed in an exterior surface of the wall and comprising a first portion extending along a first direction and a second portion extending along a second direction different than the first direction, the channel having a width between about 100 microns and about 2.0 mm.

An electronic device, comprising:

• an enclosure;
• a display positioned with the enclosure and defining a front face of the electronic device;
• and
• a haptic actuator attached to an internal structure of the electronic device and configured to produce a vibrational response including at least an audible first component within a frequency range between about 1 kHz and about 5 kHz and a haptic second component below about 1 kHz, the haptic actuator comprising:
• a movable mass;
• and
• a housing at least partially enclosing the movable mass and comprising a tuning feature configured to attenuate the audible first component of the vibrational response.