JBL Professional Control 321CT

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12 in. Coaxial Ceiling Loudspeaker with HF Compression Driver

The Control 321CT has been engineered from the ground up to deliver exceptional next-generation performance in a coaxial point source design ceiling loudspeaker.

Features

Consistent 90° broadband pattern control.
Components
• 300 mm (12 in) woofer with Kevlar-reinforcedcone with 50 mm (2 in) voice-coil.
• 25 mm (1 exit) compression driver.
Extraordinary clarity for speech and vocals with extended frequency response for music.
250 Watt power handling with high sensitivity provides high SPL capability.
Advanced high-slope crossover network for constant coverage and smooth, natural midrange.
Clean, contemporary grille and optional backbox available.

Downloads

Specifications

	Size	Uploaded
Control 321C/CT12 Spec Sheet updated: Apr 2019	1.47 MB	Apr 2019

Manuals

	Size	Uploaded
Transformer Bypass on Control 321CT, Control 322CT, or Control 328CT updated: Oct 2019	59.2 KB	Oct 2019
Control 300 Series Transformer Insertion Loss Chart updated: Oct 2019	15.4 KB	Oct 2019

Brochures

	Version	Language	Size	Uploaded
Control Contractor Brochure (2025) version A, updated: Mar 2026	A		23 MB	Mar 2026
Control 300 Brochure updated: Apr 2019			2.9 MB	Apr 2019
Control Contractor Brochure (2026) updated: Mar 2026			21 MB	Mar 2026

CAD Drawings

	Size	Uploaded
Control 300 Ceiling Speakers updated: Oct 2019	1.39 MB	Oct 2019

Compliances

	Size	Uploaded
JBL Control Series Passive Speakers DoC updated: Dec 2019	179 KB	Dec 2019
Control 300 Series Declaration of Conformity updated: Oct 2019	92.7 KB	Oct 2019

Software

	Version	Size	Uploaded
Distributed System Design (DSD) version 3.9, updated: Nov 2025	3.9	612 KB	Nov 2025

Ease Files

	Size	Uploaded
Control 300 Series GLL Files updated: May 2024	1.08 MB	May 2024

User Guides

	Size	Uploaded
Control 300 User Guide updated: Apr 2019	2.02 MB	Apr 2019

Accessories

	Version	Size	Uploaded
Ceiling Speaker Accessory Guide version 2026-04, updated: May 2026	2026-04	570 KB	May 2026

Install Guides

	Size	Uploaded
Control 321 & 322 Installation Guide updated: Apr 2019	574 KB	Apr 2019

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Parts & Service

Specifications

Frequency Range (-10dB)	34 Hz – 18 kHz
Power Rating	IEC Long-Term System Power Rating: 250 W continuous pink noise (1000 W peak), 2 hrs 200 W continuous pink noise (800 W peak), 100 hrs
Transformer Taps	68W, 34W, 17W, (& 8.5W @ 70V)
Frequency Response (±3 dB)	47 Hz – 16 kHz
Coverage Angle	90° conical, constant directivity
Directivity Factor (Q)	8.7 (1k - 16kHz)
Directivity Index (DI)	9.4 dB (1k - 16kHz)
Sensitivity	94 dB (1 kHz - 16 kHz)
Crossover Network	1.8 kHz, 3rd order (18 dB/oct) high-pass plus conjugate to HF, 2nd order low-pass to LF
Dimensions (H x W x D)	366 x 366 mm (14.4 x 14.4 in) square baffle x depth from back of baffle of 240 mm (9.5 in)
Maximum SPL (1m)	118 dB (top 70V/100V tap)
Input Connectors	Screw locking barrier strip for bare wire
Drivers	LF Driver: 300 mm (12 in) HF Driver: compression driver, 25 mm (1 inch) coil
Color	White
Safety Agency	Suitable for use in air handling spaces per UL1480, UL2043, NFPA90 & NFPA 70 when installed with UL listed backcan such as JBL MTC-300BB12. S7232/UL Listed, Signaling Speaker. Transformer UL registered per UL1876. In accordance with IEC60849/EN60849.
Backcan	formed steel (wood-lined; accessory)
Baffle/Rim	Metal, driver pre-mounted to baffle, ported.
Ceiling Cutout Size	378 x 378 mm (14.9 x 14.9 in) (for MTC-300BB12 backcan)
Included Accessories	Ported baffle pre-attached, transformer on 321CT.
Optional Accessories	MTC-300SG12 Grille, square contoured, white. MTC-300BB12 Backbox, 80 liters (3 cubic feet) MTC-300T150 Transformer, 150 W for use with 321C.
Plenum Usage	Yes, with accessory backcan

Accessories

MTC-300BB12 | 3 Cubic Ft. Backbox for Control 300 Series 12 in. Drivers

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3 Cubic Ft. Backbox for Control 300 Series 12 in. Drivers

Professional Series

Extra-thick 16 gauge metal construction.
Lined with 12 mm (½ inch) thick MDF to eliminate resonances and to provide extra bass response.
Knockouts on top and all four sides.
Dual mounting system for baffle.
Mounting platform for an optional high-power 70V/100V transformer.

Documentation

MTC-300BB12 Spec Sheet [2.54 MB]
Accessing the Conduit Knockouts [116 KB]
Control 300 Ceiling Speaker Backboxes / Backcans [1.1 MB]
Control 300 Ceiling Speakers [1.39 MB]
JBL Brackets [152 KB]
Brackets Declaration of Conformity [141 KB]

MTC-300SG12 | Square Grille for Control 300 Series 12 in. Drivers

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Square Grille for Control 300 Series 12 in. Drivers

Professional Series

Rugged 19 gauge metal construction for enduring reliability.
Sculpted design for an elegant appearance and perfect for any decor or architectural setting.
Zinc underplating provides a rust and scratch resistant surface for years of maintenance free wear.
Powder coat final finish minimizes scratching and can easily be repainted to match any room color.