Enable Classic Startup Ringtone on New MacBook Pro With Terminal Command
Apple decided to remove the startup beep on the new MacBook Pro , which, in addition to being a mainstay for the Mac for years, has always helped fix boot issues . Luckily, you can get the sound back using the Terminal command.
All you have to do is open Terminal (Applications> Utilities) and enter this command:
sudo nvram BootAudio =% 01
This will return a startup sound, along with the suggestion that it should also help you troubleshoot any issues.
Re-enable Classic OS X Start Tone in 2016 MacBook Pro | Windows clan