You might check with a control-valve manufacturer. Both Fisher and Kimray give you that number for their valves if you ask. They might have some software that they would give, sell, or run for you.
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).