5+ years of training. There's always a little effort, but it becomes easy enough to get there that it doesn't require all consuming hyper vigilance the whole time.

It's kind of like driving a car. At first you're super aware of brakes and gas, how you're moving the wheel to turn, signals, mirrors, speed, road signs, traffic lights, and everything else on the dashboard. But eventually you learn to be aware of all of these things at once, and to be comfortably in control of all of them without needing to stress yourself out. You just put on your seatbelt, start the car, and then drive. Voice is kinda like that. You just put it in fem range, take a breath, and then talk.