1. SpeakerTransforms electrical energy into sound energy. It can produce both loud and soft sounds depending on the input signal.2. MicrophoneConverts sound energy (loud or soft voices) into electrical signals for recording or amplification.3. Musical Instrument (e.g., Guitar)Converts mechanical energy (strumming or plucking strings) into sound energy that can be loud or soft.4. HeadphonesTransform electrical signals into sound energy that can be heard softly or loudly depending on the volume setting.5. AmplifierTakes a weak electrical audio signal and increases its power, producing louder sound energy from a soft input.