R.O.'s have not been generally characterized for noise. With thin plate designs, not only the jet noise but the FIV of the plate must be considered.
It is a real problem. Basically, you have to assume that all critical flow applications will be noisy and consider use of a control valve instead. In liquids, cavitation and hydrodynamic noise is a serious issue.
Where R.O.'s are used as a valve free restriction, you will be forced to use cascaded restrictions or rely on proprietary designs (thick plates/restriction tubes).