Krieger recommends the following closers and guidelines for gaining maximum performance from your sound proof doors. Please note that all U.L. rated sound proof doors will require a closer to be U.L. certified.

Parallel arm closers:

Mount the arm bracket to the "Z" brackets furnished by Krieger, or use a top jamb mounted closer. Never mount closer arm shoe directly to the seal cover.

Rixon floor closers:

The arm which must mount in the bottom of the door precludes the use of a mortised door bottom. Krieger does not recommend using this hardware item on sound proof doors.

Concealed overhead closer:

Krieger cannot certify an STC rating for these closers because they mount directly into the head of the frame and prevent a continuous perimeter seal resulting in sound leaks.

Closers recommended for use with Cam lift hinges:

Since cam lift hinge assemblies require closers that allow for 3/8" vertical movement, Krieger offers the following manufacturer and model recommendations:

LCN: 4010, 4020, 4041 Super Smoothie
Dorma: 640, 540, 7600, 7800, TS83
Corbin/Russwin: DC2000, DC3000, DC4000
Norton: 7500, 8500
Sargent: 250, 251, 350, 351, 1230, 1231, 1250, 1251

NOTE:
Krieger has not received any documentation from Norton or Corbin/Russwin validating Krieger's recommendation)

Closers not recommended for use with Cam lift hinges:

LCN: 4110, 4041 Cush-N-Stop, 4040 Extra Duty Arm
Closers with a large bolted knuckles at the elbow that will not allow 3/8" vertical movement.
Slide track type closers
Overhead stops