A wearable electronic device (100; 200), comprising: a microphone array (120; 220), configured for sensing an environmental sound; a plurality of stereo speakers (140; 240); and a control circuit (160; 260), coupled to the microphone array (120; 220) and the speaker, wherein the control circuit (160; 260) is operable to: calculate a distance and a directional angle from a source of the environmental sound to the wearable electronic device (100; 200) according to the environmental sound sensed by the microphone array (120; 220); generate an effect sound by modifying the environmental sound; process the effect sound for simulating the effect sound to be originated from a virtual location with the distance and the directional angle relative to the wearable electronic device (100; 200); and broadcast the processed effect sound through the stereo speakers (140; 240); wherein the wearable electronic device (100; 200) is a head-mounted display device comprising a displayer (180; 280), the displayer (180; 280) is configured for showing a virtual reality scene, wherein the effect sound is generated by modifying the environmental sound according to an audio tone corresponding to the virtual reality scene; and wherein the processed effect sound is combined with a virtual world sound corresponding to the virtual reality scene to be broadcasted through the stereo speakers (140; 240). a microphone array (120; 220), configured for sensing an environmental sound; a plurality of stereo speakers (140; 240); and a control circuit (160; 260), coupled to the microphone array (120; 220) and the speaker, wherein the control circuit (160; 260) is operable to: calculate a distance and a directional angle from a source of the environmental sound to the wearable electronic device (100; 200) according to the environmental sound sensed by the microphone array (120; 220); generate an effect sound by modifying the environmental sound; process the effect sound for simulating the effect sound to be originated from a virtual location with the distance and the directional angle relative to the wearable electronic device (100; 200); and broadcast the processed effect sound through the stereo speakers (140; 240); calculate a distance and a directional angle from a source of the environmental sound to the wearable electronic device (100; 200) according to the environmental sound sensed by the microphone array (120; 220); generate an effect sound by modifying the environmental sound; process the effect sound for simulating the effect sound to be originated from a virtual location with the distance and the directional angle relative to the wearable electronic device (100; 200); and broadcast the processed effect sound through the stereo speakers (140; 240); wherein the wearable electronic device (100; 200) is a head-mounted display device comprising a displayer (180; 280), the displayer (180; 280) is configured for showing a virtual reality scene, wherein the effect sound is generated by modifying the environmental sound according to an audio tone corresponding to the virtual reality scene; and wherein the processed effect sound is combined with a virtual world sound corresponding to the virtual reality scene to be broadcasted through the stereo speakers (140; 240).