Product Overview

The JBL Control 328CT is an 8-inch coaxial ceiling speaker with a built-in 70V/100V transformer, designed for distributed voice and foreground-music systems in commercial AV installations. It pairs a 200 mm (8 in) Kevlar-reinforced low-frequency cone with a 25 mm compression driver for clear speech and program audio across wide listening areas. With 250 W power handling, 120 constant-directivity coverage, and a factory transformer, this 70V/100V coaxial ceiling speaker drops directly onto distributed lines without external matching hardware. It is built for clean integration into standard ceiling-grid layouts.

Product Description

The Control 328CT is the transformer-equipped version of JBL’s 300-series coaxial ceiling platform, engineered for installations that need both pattern control and direct distributed-line operation. The coaxial design keeps the high- and low-frequency sources time-aligned, while the shaped baffle acts as a high-frequency waveguide to deliver consistent 120 broadband coverage with true coaxial behavior. As a transformer-equipped ceiling speaker, it carries a built-in multi-tap transformer with 70V taps of 68 W, 34 W, 17 W, and 8.5 W (100V: 68 W, 34 W, 17 W), set through a removable locking connector with screw-down terminals for fast, pre-wired installation. With 250 W continuous power handling and a 118 dB maximum SPL (124 dB peak), it provides headroom to overcome ambient noise in atriums, retail, and large meeting spaces. The driver ships pre-mounted to a ported round metal baffle, and when paired with the UL-listed MTC-300BB8 backcan it is suitable for air-handling (plenum) spaces per UL1480, UL2043, and NFPA 90/70 making it a practical plenum-rated ceiling speaker for code-sensitive deployments. For projects running discrete low-impedance zones rather than distributed lines, the 8-ohm JBL Control 328C ceiling speaker is the same driver without the onboard transformer.

Key Features

• Built-in 70V/100V transformer Onboard multi-tap transformer (70V: 68/34/17/8.5 W; 100V: 68/34/17 W) for direct distributed-line operation.
• 8-inch coaxial driver array A 200 mm Kevlar-reinforced LF cone and 25 mm HF compression driver share an axis for time-aligned, full-range output.
• 120 constant directivity A shaped baffle waveguide maintains an even pattern across frequency for consistent off-axis intelligibility.
• 250 W power handling High thermal and mechanical headroom (1000 W peak) supports demanding program material.
• 118 dB maximum SPL Output to 124 dB peak overcomes ambient noise in high-traffic commercial spaces.
• Plenum-rated operation Suitable for air-handling spaces per UL1480, UL2043, and NFPA 90/70 with the UL-listed MTC-300BB8 backcan.
• Fast-wiring connector A removable locking connector with screw-down terminals allows pre-wiring and clip-on installation at the chosen tap.
• Pre-mounted ported baffle The driver ships on a round metal baffle to reduce labor time on site.

Typical Applications

• Commercial meeting space Distributed speech and music coverage across lobbies and gathering areas.
• Conference room Clear program and voice reproduction in standard ceiling-grid layouts.
• Multi-purpose room Flexible foreground audio with headroom for varied program material.
• House of worship Even distributed coverage for speech and music in larger rooms.
• Training room Intelligible voice reinforcement across wide seating areas.
• Government space Reliable distributed paging and announcement coverage.

Technical Specifications

What’s in the Box

• JBL Control 328CT 8″ coaxial ceiling loudspeaker (driver pre-mounted to ported baffle)
• Removable locking input connector with screw-down terminals
• Installation/spec documentation

Note: Backcan and grille are sold separately as optional accessories MTC-300BB8 backcan, MTC-RG6/8 round or MTC-SG6/8 square grille.

Frequently Asked Questions

How does the 328CT differ from the 328C?
The 328CT includes a built-in 70V/100V multi-tap transformer for distributed-line systems, while the 328C is the same 8-inch coaxial driver configured for 8-ohm low-impedance operation.

What transformer taps are available?
70V taps of 68 W, 34 W, 17 W, and 8.5 W, and 100V taps of 68 W, 34 W, and 17 W, selectable at the connector.

Is it plenum-rated for installation above a drop ceiling?
Yes. With the UL-listed MTC-300BB8 backcan it is suitable for air-handling (plenum) spaces per UL1480, UL2043, and NFPA 90/70. The backcan is sold separately and is also required for proper low-frequency loading.

Does it require a separate grille?
The round metal baffle is integral; contoured grilles (MTC-RG6/8 round or MTC-SG6/8 square) are available separately to match the installation aesthetic.

What warranty and support apply?
The Control 328CT carries JBL Professional’s manufacturer warranty. For tap planning, backcan selection, and integration support, contact our team at sales@ or browse the full JBL Professional collection.