Irrigation Solinoid Zone Valve "Hammering"

Hi Terry-
My Irrigation System (6 Zones with Hardie RD-600 Controller) are innitially "hammering across all 6 zones" for about 5-8 seconds when either in auto or manual mode. The system is about 10-12 years old and I did'nt initially have this problem. The street water pressure is about 55 - 65psi. I believe the valves are also "Hardie". I will check to see model nos. Possibly..... Does the diaphrams / solinoids need replacement to correct this chatter???? The piping in the basement really chatters at startup across all zones. I appreciate your advise!
Thanx..... Geo

chatter

IF it happens with all the valves then the problem is probably in the piping to them, or more specifically, the antisiphon valve that the water should flow through first.