What's up with the beeping countdown with 5 seconds left in the shot clock? (Sun/Blazers game)?

Watching the Suns/Blazers game... Is that playing in the arena?? Or is that just for us to hear at home? I've played ball my entire life and played college ball and have never heard of that. If it's in the arena I just feel like it's helping the players too much! How long has this been going on? I need answers, lol. That's changing the sport!