Input device and sound output system

A sound output system comprising:

• an input device comprising a touch device configured to receive a user operation, an actuator configured to apply a vibration corresponding to a drive voltage to the touch device, and a processor configured to control driving of the actuator;
• a receiver configured to receive a radio signal and acquire a reception signal of the radio signal;
• and
• a sound output device configured to reproduce and output an audio signal based on the radio signal,
• wherein the processor is configured to:
• apply a first voltage as the drive voltage to the actuator to vibrate the touch device with a first vibration in response to a touch-down during a touch operation, the touch-down in which a pressing force of a predetermined value or more is detected from start of touch to the touch device;
• apply a second voltage as the drive voltage, the second voltage being lower than the first voltage to the actuator to vibrate the touch device with a second vibration in response to a touch release during the touch operation, the touch release in which a pressing force of a value lower than the predetermined value after the touch-down is detected, and
• perform a mute processing on the audio signal when the first vibration is generated.