CSM-21 (discontinued)

Public Address Mixer

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The JBL® Commercial CSM-21 offers fixed I/O, pre-configured architecture, full stereo or mono operation, flexible routing and control of multiple audio sources, simple front-panel configuration and control without the need for a computer, compatibility with the CSR wall controllers, compatibility with the CSPM paging microphones, and optional duplication of audio channels to another device via a Cat5 cable.

The CSM-21 features two stereo music inputs with gain control and clip LEDs, and one stereo output with an active crossover and a dedicated subwoofer output.

Two additional inputs are provided for music override. First, a mic input with phantom power and gain control can be routed to the output zone, ducking the music by a user-configurable amount. Second, a line input allows high-priority ducking of all sources, which is ideal for alarms.

Dedicated controls for music EQ and dedicated controls for global mic EQ allow the frequency content of each input type to be customized independently. LevelGuard™ is provided to retain consistent volumes between the various inputs, and AutoWarmth™ is provided to ensure full fidelity at all zone volume levels.

A Zone Remote port facilitates connection of the CSR wall controllers, which can provide source selection and/or volume control. Source select, music level, and mic level can also be controlled on the front panel. For additional control, two logic inputs facilitate page steering and music muting via contact closure.

Two RJ-45 Link ports allow multiple CSM devices to be linked to increase the number of output zones. Linking CSM devices shares the inputs from the main devices over Cat5 cable and eliminates the need for Y-cables.

An included security plate can be placed over the front panel controls to avoid uninvited changes to a commissioned system.


  • 2 Stereo Inputs
  • 1 Mic Input
  • 1 Line Input for Priority Audio
  • 1 Stereo Output with Dedicated Subwoofer Output
  • Quick and Simple Configuration via Front/Rear Panel Controls
  • Digital Processor with Analog-Style Control
  • Music EQ
  • Global Mic EQ
  • AutoWarmth™ and LevelGuard™
  • Optional CSR-2SV wall controller provides source selection and volume control
  • Optional CSR-V wall controller provides volume control
  • Contact Closure Control
  • Link Bus for Input Sharing
  • Security Plate for Front Panel Lockout (included)


  Version Language Size Uploaded
file type icon CSM-21 Cut Sheet-Chinese
zh updated: 2月 2024
  zh  734KB 2月 2024
file type icon CSM-21 & CSM-32 Brochure
updated: 4月 2020
    3.61MB 4月 2020
file type icon JBL Commercial Brochure
updated: 4月 2020
    1.64MB 4月 2020
Application Guides
file type icon Series Application Guide (English)
version 1.7, updated: 4月 2020
1.7    6.89MB 4月 2020
file type icon Series Application Guide (Chinese)
version 1.7, updated: 4月 2020
1.7    11.5MB 4月 2020
User Guides
file type icon CSM-21 & CSM-32 User Guide - Chinese
zh updated: 4月 2020
  zh  10.9MB 4月 2020
Owner's Manuals
file type icon CSM-21 & CSM-32 User Guide - English
en updated: 4月 2020
  en  6.82MB 4月 2020

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Parts & Service


HARMAN Professional Solutions:

CSM-21 (discontinued)

Public Address Mixer