Your ProAc's have a more forward and direct sound to them. If you're used to listening to them, changing to a different speaker can show this quality in a very abrupt way.
You also need to take your room, electronics and placement into consideration. The 1sc's are far more forgiving of placement than the Harbeth. Try placing them closer together and moving your listening chair to a more nearfield position.
You also need to take your room, electronics and placement into consideration. The 1sc's are far more forgiving of placement than the Harbeth. Try placing them closer together and moving your listening chair to a more nearfield position.