Just fit a tensioner for a single speed conversion and surprised at the noise from the jockey wheel. It's an 11 tooth plastic jockey wheel. Alignment looks fine. Would a larger jockey wheel be quieter?
They are under quite a bit of tension, so will be noisy.
My only complaint about Shimano drive trains is jockey wheel noise from. A squeak from the bushing. The posh ceramic ones don't have this. Other brands have ball bearings which will quieter as well
This noise is each time the link makes contact with the jockey wheel. Sounds like plastic rubbing in the chain (nothing is rubbing).
My SS tensioner used to make a sort of thrumming noise when I pedalled, then I got used to it 🙂
I've now got a Trickstuff Exzentriker, much better all round than the tensioner, though a lot more spendy.