I have low water pressure and water pipes making a terrible noise. I have installed hammer arresters, they did not help---so please help me

Thanks

Please desribe the noise, water hammer is normally just one load thump when a valve is quickly closed. Is the pressure low everywhere including your outside spigot?

I have low water pressure and water pipes making a terrible noise. I have installed hammer arresters, they did not help---so please help me

thanks
First answer Bals questions and then I have one. What types of pipes do you have? Copper? Plastic? Or galvanized? How old? Regards, Tom

The water pressure is at 35 and I have galvanized pipes. The pipes did not start to rattle until we had the bathroom remodeled. The contractor left the old shower pipes in the wall and I think they have air in and possibly left them loose causing them to rattle. The noise is coming from where the pipes come through the floor into the shower/tub. I have checked all of the new plumbing and all of the pipes are secure and not touching. I have also bled the system which did not help. The pipes rattle no matter which faucet is turned on or off inside or outside. I have had 2 plumbers out to see if they could fix it but they did what I had already done plus I had to pay them. I don't mind paying to get it fixed but no one can guarantee they can fix it. We are trying to sell the house and I know it will be an issue with the new owners ( if we ever can sell) Want to buy a waterfront house in Florida?
Thanks for the help.