Its a friendly reminder to turn your phone to SILENT (NOT VIBRATE) when you enter the studio., WHY? , Because we often have private training or classes taking place in one side of the studio and My iPhone Doesn't Vibrate! Here's The Real Fix. Why iPhone May Not Vibrate in Silent Mode and How to Fix It Cool phone tip I just learned You can keep your phone on silent and still hear calls or texts from specific people like family, close friends, or co commanders . Here's