Pressure regulator

My home was built in 2005. Ever since it was new we have had noise coming from our water pipes that sounds like hammering. This noise only happens when the sprinklers are used. The builder tried to fix it in the first year without any luck. They installed a pressure regulator up in the flowerbed by the house. That never did anything by the way. So I decided this year was the year I was going to figure this thing out. I bought a pressure gauge and hooked it up to a outside hose bib. The pressure registered at 110psi. I then went to the box where the builder installed the regulator and turned the water off. This regulator does not look like any of the regulators I have seen on the net. It looks more like a gate valve or globe valve. I had someone stand at the hose bib with the gauge installed while i backed off the regulator. I would turn it a 1/4 turn and then ask what the pressure was. I made a full turn before i got any pressure registering at the gauge. And it went from 0 to 110 with no adjustment in between. I can email pictures if you need them. I am trying to get my pressure down to around 65psi. I am not sure if the pipe is 3/4" or 1" I am all for pulling the garbage out that the builder installed and putting in something that will best fit my needs. I am just not sure what regulator and set up I need to accomplish this. Please advise.

Thank you.

The pressure is adjusted on the contactor switch if your on well water and on the pressure regulator that's near the main incoming water meter if your on city water.
No form of gate, globe, or ball valve will control pressure, they can only control flow.
http://www.irrigationtutorials.com/sprinkler03.htm

Sounds like you need a real pressure regulator installed and not a valve....

you can install pressure regulator to reduce water pressure, which reduces the noise. You can also contact some professional to fix the problem.