I have got quiet used to the noise now after 18 months and I think I would miss it if it was no longer there. It is like the platters moving across the drive followed by a small 'bump' noise, then the whole process starts again.
Probably does take around 8 seconds. Why don't you record it on your phone Minstrel then upload it, (if this is possible) and we could listen to see if it's the same noise.