I'm trying to deliver real-world advice. If the water hammer was extreme beyond common experience, it would have already done physical damage, like blowing a zone valve apart, or completely off its threaded supply connection.Securing the indoor plumbing from movement is job one.
No doubt that if a pipe is physically getting moved, it needs to be secured.
But over time, water hammer can lead to fatigue failure. Sure, the level of the water hammer can be low enough that 2 or 3 bangs are not going to "blow a gasket". But 2 or 3 thousand bangs over the life time of an irrigation or plumbing system might. Just because a water hammer hasn't broken something yet is NOT a reason to decide to ignore it thinking you can just live with the noise. Eventually, water hammer will break something. It's just a question of time. Will it be days, years, or decades?
Also, note that there is banging when the zone is first opened, and that is not water hammer. It is something of an oscillation you can sometimes see when a system is first opened in the spring, where there is no water in the zone for the supply to 'push' against. When it happens on a recurring basis, you look to make changes. Installing check valves in the heads is one obvious choice nowadays, to keep a zone full of water, so there's something to 'push' against. Throttling down a zone valve flow control is another option. Changing zone valves is another.
Even with check valves I'm still getting an audible noise inside the house when a zone comes on.
My irrigation system connects to the water main at the street just after the water meter. From there it goes through a DC and then 15' of pipe to reach the manifold. I also have a pressure regulator as the water main enters the basement.
On a quiet morning, you can "hear" through out the house when the irrigation system turns on. It's not a "bang" noise, more of a "whine".
Here's what I THINK is happening and would appreciate any further insights: There is water in the pipes, but the water before the valve is about 70psi and the water after the valve is about 0.5psi. When the valve opens, that 70psi momentarily drops until the latteral gets pressurized. But in the mean time, the pressure drop propogates back to the main line and all the way to the house hold plumbing. The "whine" I am hearing is the sound of the water pipes repressurizing. The whole thing happens in about 1 second.