YouTube works only in Chrome or Edge on a computer or Chromebook. Safari, Firefox and iPads play the built-in recordings but cannot connect YouTube.
Headphones give the best sound, and are needed for anything that treats each ear differently.
Both simulators have built-in recordings, so you can start listening right away. With Simple view switched off, the simulators also let you connect a YouTube video, upload your own audio or video files, or use the microphone.