DUMBO is an application that is able to hear the outside sounds when you're listening to music through headphones. If you're listening to music in your office or school by Mac or think you can get much more work done when listening to music in the office, but you didn’t notice someone trying to speak to you. DUMBO can help you with that.
After running the application, click “Enabled” on the menu bar, Dumbo will start picking up sound built-in microphone in Mac. You can hear the outside sounds through your music. You can’t pick up soft sound but easy to catch if someone calls your name or a bell rings.