[MAteo9944]

The honking noise in the valve is caused by the diaphragm not opening fast enough. In sprinkler valves the port that opens to let the diaphragm open is not very big. This is to prevent water hammer, but since you are using it for air you don't don't care about water hammer. When I make my cannons I usually remove the solenoid, epoxy the port, and cut my own larger port in the top of the valve. I then screw in a pneumatic fitting and use a KoP valve to fire it. This will get rid of the honking noise and increase the valve's performance.

If you decide you need a bigger valve you can use two of the 1" sprinkler valves with T-connectors to fake a bigger valve.