Commonly, there is no distinctive audible warning as regards brushing hard; however, the shyn brush does give a beep warning. Asides from the shyn brush, the only form of an audible warning from other brushes is the change in the motor sound when the pressure is higher and when it is not. And if you are not observant, you may not notice the change in the motor sound. So, just stick to the light, and your app as the case may be.