Pipes knock when I run my washing machine - tried adding water hammer suppressors to both the cold and hot line and no luck - still knocking.

I was reading a post here a week or so ago and heard about water hammer suppressors for the first time, and figured that had to be why my pipes knock when I run the wash. I was happy to have a solution bc it knocks most loudly in my sons room - his bedroom is above the laundry room. But unfortunately no dice, they didn’t work at all. Any other suggestions? Thanks so much.