Usually very little. Ohio's standards keep the fan out of the living space, in an attic, a garage that is not under a room, or outside, mounted to limit vibration. Most sound people notice is air at the discharge or a fan that is wearing out.
More detail
Several of Ohio's mitigation rules are quietly noise rules: the main pipe must be at least 3 inches in diameter to avoid flow noise, the finished system must run at a reasonable noise level, fans sit in vertical runs, and they attach with removable couplings that help keep vibration out of the framing. On a Columbus house the real choice is usually between a fan on an exterior wall, which is simple but can put the pipe within earshot of a bedroom window, and an interior chase up to the attic. Walk the proposed route before the install and point out which rooms sit next to it. A fan that was quiet for years and has started to hum is a different problem, covered in why a radon fan gets noisy.