A:AnswerIt is silent when recording. You cannot record and charge at the same time. The device is charged by a retractable USB connector. When plugged into a USB port a "Connecting" screen appears. I have not been able to start a recording while it is plugged in. I'm not sure if it would work while plugged into a USB wall charger, but I'm guessing the same thing would occur.
A:AnswerHi, Che, This digital voice recorder supports the .mp3 audio format. It is tested to work well with macOS v10.11 to v10.14: https://helpguide.sony.net/icd/u57/v1/en2/contents/TP0002410943.html. -Vincent