If anything it's worse in the middle, then improves slightly in the lowest gears...
You're not mixing Shimano and Campy parts together are you ? I did, had just the symptoms you describe, and it drove me MAD(er).
Thankfully, no!
@The.Gren started
London Fixed Gear and Single-Speed is a community of fixed gear and single-speed cyclists.
If anything it's worse in the middle, then improves slightly in the lowest gears...