Well technically yes. You can cut a hole in the side of the case and hook an aftermark fan speed adjuster into your power supply and connect that to the fan. If you are referring to a software setting I do not think so. Maybe someone else will know.
An Applecare tech once told me that there's an app they (and repair centres) can use to re-calibrate the fans. Not sure whether that's true or not! And I'm sure if it is, it's not a commercially available app.