From what I understand, the newer 2ce Sig II is a step closer to the 3A Sig. I think it has the same tweeter & maybe midrange too. The bass is still where the big difference is.
I've owned 1c's, 2ce's, 2ce Sigs and currently 3A's. IMO, the 3A's are the best, top to bottom. They have a smoother more detailed top end, better integrated, more realistic mid-range, as well as deeper, tighter bass.
I've owned 1c's, 2ce's, 2ce Sigs and currently 3A's. IMO, the 3A's are the best, top to bottom. They have a smoother more detailed top end, better integrated, more realistic mid-range, as well as deeper, tighter bass.