The church contains two organs, one on the north side and one at the west end. The smaller one, called the "Koororgel" (choir organ), was built in 1511 by Jan van Covelens, and is built against the north wall of the church. It is the oldest playable organ in the Netherlands. The larger organ at the west end of the church is was built by Jacobus Caltus van Hagerbeer, finished in 1645. The magnificent casework, which unusually stretches from floor to vault and makes the organ part of the architecture of the church, was designed by
Jacob van Campen, a leading architect of the time. The enormous canvas shutters were painted by
Caesar van Everdingen. The organ was rebuilt in 1723 by
Frans Caspar Schnitger. He left the casework much as it was, but created an organ in the North German style within the old case. He reused much of the old flue pipes and added new mixtures and reeds were new. The organ has not been changed much since then, and is rare in that 90 percent of the original material, pipework, action, soundboards, case, survives. As such it is one of the most important organs in the world. It is the subject of a documentary made in 2013 and released on DVD by Fugue State Films as "Alkmaar: The Organs of the Laurenskerk". == Carillon ==