Patrick, pretty much all of the non-Mac apple products bong when power is applied. I understand why, to signal to the user that the charge is actually connected, particularly for wireless charging for the Watch and wireless charging iPhones. While it's not terribly critical to get the charger properly aligned, it is a good indicator that you have the Watch puck in place, or the iPhone properly near the QI charging coils. The problem is that there isn't any way to NOT have the bong, even when you really don't want it, other than to turn off the sound completely. But the process of turning it back on could cause the iPhone to become dislodged or misaligned with the charger such than when the sound is back on it may bong if you then adjust to get it aligned again. It's basically a no-win if you want silence. Even in Accessibility there is no setting to change it to a light flash instead of the tone. Basically, the bong is there to stay, until Apple decides to allow some configuration of it.