JBL Professional Control 321C - 12″ Coaxial Ceiling Speaker with HF Compression Driver and Constant 90° Coverage
The JBL Professional Control 321C is a coaxial point-source in- ceiling loudspeaker designed from the ground up to deliver high SPL , excellent intelligibility , and exceptionally consistent 90° coverage . The shaped metal baffle acts as a waveguide: the 12" cone itself guides the high frequencies and, together with a 1" (25 mm) titanium-diaphragm compression driver , maintains directivity and timbre across the entire frequency range. The 300 mm woofer with a Kevlar-reinforced cone and 50 mm voice coil ensures reliability, low distortion, and extended response for both music and speech. The steep crossover provides a smooth, natural midrange, crucial for clear speech reproduction in demanding environments.
Installation is quick thanks to EZRail™ , which secures the speaker during mounting, and the removable multipin connector with screw terminals for pre-wiring and line pass-through. The 321C operates at low impedance and is plenum-ready when installed with the MTC-300BB12 back box . For integration into 70/100 V systems, JBL offers the MTC-300T150 external transformer . Its 94 dB sensitivity, 250 W IEC power rating (2 h) , and maximum SPL of 118 dB continuous / 124 dB peak allow for coverage of large areas with fewer points, optimizing costs without sacrificing performance.
Main features
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90° conical coverage of constant directivity for tonal uniformity throughout the listening area.
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Premium coaxial system : 12″ Kevlar woofer (VC 50 mm) + 1″ compression driver (titanium diaphragm, ferrofluid ).
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High performance : sensitivity 94 dB , 250/200 W IEC (2 h/100 h) and 118/124 dB (average/peak).
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Extended response : 47–16 kHz (±3 dB) and 34–18 kHz (−10 dB) for full-bodied music and voice.
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Advanced crossover at 1.8 kHz (HP 18 dB + conjugate / LP 12 dB) for a smooth and natural midrange.
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Professional installation : 366 × 366 mm metal baffle ported with EZRail™ , locking connector and MTC-300BB12 backcan option ( 378 × 378 mm cut).
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Plenum & regulations : suitable for air handling spaces (UL1480/UL2043, NFPA-90A/70) when used with UL listed backcan.
Product benefits
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Fewer speakers per zone : the stable 90° pattern reduces spots without losing clarity or coverage.
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Superior intelligibility in ads and voice thanks to coaxial design and broadband directivity control.
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Integration flexibility : low impedance operation or 70/100 V option with external transformer.
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Agile and safe work : assisted assembly, line crossing and official accessories for backcan and contemporary grids.
Use cases
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Retail, restaurants and hotels with background music and clear signs on large surfaces.
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Offices, education and healthcare with uniform requirements, sufficient SPL and plenum compliance.
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Convention centers and museums that demand high performance with a discreet ceiling aesthetic.
Frequently Asked Questions
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Does it include a 70/100 V transformer? No. For distributed lines, use the MTC-300T150 or choose the Control 321CT version with integrated transformer.
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Is it plenum-ready? Yes, when installed with the MTC-300BB12 or other UL-listed back box per UL1480/UL2043 and NFPA-90A/70.
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What optional grille is available? The MTC-300SG12 (square, contoured) offers a contemporary aesthetic.
Project description
JBL Control 321C coaxial ceiling loudspeaker (low impedance), 90° coverage; frequency response 47–16 kHz (±3 dB) / 34–18 kHz (−10 dB) ; sensitivity 94 dB (2.83 V/1 m, half-space); Q 8.7 , DI 9.4 dB ; IEC power rating 250 W (2 h, 1000 W peak) / 200 W (100 h, 800 W peak) ; max. SPL 118 dB continuous average / 124 dB peak; crossover 1.8 kHz (HP 18 dB + conjugate / LP 12 dB). Transducers: LF 300 mm Kevlar (VC 50 mm) + HF compression 25 mm (1″ exit, JBL 2412H-1). Ported 366 × 366 mm baffle. Installed depth from the rear of the baffle 223 mm ; cut in ceiling with backcan 378 × 378 mm ; suitable for plenum with MTC-300BB12 .
