New to Subaru is this noise normal?

[sharkbait]

So I've finally managed to join the gang I've got a forester 2.0d xc boxer. It's my first time driving a 4wd. When I'm driving it sounds like I'm driving on snow tyresas I speed up and slow down, as is in can hear the same kind of rumble I'm guessing it's just a different noise to what I'm used to with the drive train I've always had front wheel drive. Any advice is very welcome please. 

[Judd]

Could well be tyre noise, but you won't confirm one way or another till you slip another set of tyres on and see if the noise changes.

Our Foz is on its winter set at the moment and it sounds like a wheel bearing or diff is on the way out, open the window on on a smooth road in a built up area for best effect, but when the summer set go back on next month that noise will vanish completely same as every year, unfortunately the ride quality will go down because the summer set are 17" 55 aspect as against 16" 60 aspect, can't have everything.

Seeing how easy these are to work on, in the meantime it wouldn't hurt to check the oil levels throughout the transmission and if necessary top up or even replace the oils.

[sharkbait]

Thanks Judd,

If I had winter tyres on I'd agree completely but I've just got normal tyres on, but sounds like winter tyres. My previous cars were very quite inside the cabin but this seems noisier especially with that particular noise. Just wondering if it's normal. Unfortunately I won't be home for a while to check the levels but that will be my first port of call.