aluminium flex duct or insulated flex duct?

[fireburner23]

So......is aluminium flex duct or insulated flex duct quieter?

 

[Dr Dog]

insulated by far

 

[darthvapor]

remember you could also get a duct muffler whick quiets things up a lot. also you could use bigger ducting and run the fan at a slower speed to achieve the same volume but with less velocity and noise.

 

[NiteTiger]

insulated by far

 

[fireburner23]

Thanks that helps. I have made a duct muffler as well, but I am thinking that having the insulated flex duct will help to further quiet things as well.