I have had my oreck over five years now but don't use it a great deal owing to changing over to laminate flooring. However, I have noticed how much louder it seems to be getting. It has always been fairly loud in use but I wonder whether a service would help detect a fault as it is doing my ears in!
Carpets are great noise mufflers for vacuums. Most of the noise comes from the bottom of the vacuum, and when you don't have carpet under there, it is at least three times as loud.
I have a noise problem in mine, but I think the reason is related to a vibration problem too. The handle gets really uncomfortable because it feels like something is ready to rust apart. I can hear it squeak when I shut it down