A first (71) and a second (72) bale speed sensor are provided in a segment (41) of the baling chamber (1) of an agricultural baler. The first sensor (71) is positioned at an upper part, while the second sensor (72) is positioned at a lower part of the baling chamber (1). Respective outputs of said bale speed sensors being operationally connected to a controller (9) which is adapted to adjust based on said outputs a synchronization between the periodically forming and pushing of a slice (3) of crop material and the reciprocal movement of the plunger (5).
