In a recent update, Microsoft gave us the ability to turn off the "Power On Chime", you can also make it so the chime only plays when the Xbox One is turned on using the Voice command or the power button on the console but not the controller.
Here is How to Turn off Xbox One's Start Up Chime
- Scroll left on the Home screen to open the guide.
- Go down to the settings gear and select all settings
- Go down and select "Power & Start Up"
- Select Power and Start up
- Move down and select "Start Up Chime"
- You can now choose to have the chime played when the Xbox One is turned on with the power button on the console or voice, but not with controller, or you can turn it off.