Vibration is prevented in a multi-nip calender (1) or an array of multi-nip calendars. Each calender has a lower roll (3; 40), an upper roll (3; 30) and two or more intermediate rolls. A fiber web is conveyed through the closed roll nips of the calenders. The intermediate rolls (3) have load-relieving apparatus and the upper roll (3; 30) and the lower roll (3; 40) have loading apparatus, while loading apparatus are connected to the lower roll (3; 40) and/or the upper roll (3; 30) for loading these rolls from the outside in a direction parallel with the calender plane. The running parameters (9) influencing the calendering impulse of one or more selected roll nips (N) are intermittently or continuously changed, such that the overall calendering impulse (9) of the calender or calender array and/or the quality variables (21) of the fiber web remain substantially constant and/or within predetermined limits.