Hard to say without more information. If one is quiet and the other is noisy, at roughly the same RPM, then I can't say that the tips are travelling too fast, though 2200 RPM is darn fast on any windmill. do the two sets of blades have different airfoil? Different angle of attack? If you look at each of the 29 inch blades, do they have different angles of attack? Is the trailing edge sharp? Are the tips flat, tapered, bevelled, etc.? Have you weighed each blade?