Hvac damper types - which one is quietest
Adding a damper to a squirrel cage blower either to the inlet or outlet may sometimes increase the noise due to the flow of air past that damper. Other ideas which may work better but will cost more would be to purchase a 2 speed motor. You would get 2 fan speeds which could be selected by switch mounted where you choose. Another idea would be to install a variable speed ECM motor. This motor would yield an infinite number of speeds. You could even have a motorized damper installed that would yield complete control of the amount of air flow. These last 3 ideas, although more costly, would give you an easy adjustment of the air flow as opposed to a manual type damper.