Which pololu micro metal gearmotors are the quietest - HP carbon brush or HP precious metal brushes?

I’ve been looking at the Pololu 6V micro metal gearmotors, and was wondering if anyone knew how quiet they were?

I’m thinking of buying a 210:1 High power gearmotor, either in Carbon brush or precious metal brush, and was wondering if the metal type would impact the mechanical noise produced?

I’m using them for a project where I need minimal noise.

PS. I am an artist and have a basic understanding of electronics, and so any help is appreciated!

Hello.

We have not characterized how much noise the micro metal gearmotors produce, but from our experience the HP carbon brush gearmotors and HP precious metal brush gearmotors produce about the same amount of noise.

Grant