The KEF Ci100QS is the most compact square model in KEF’s Ci Series of architectural speakers, belonging to the Soundlight Q Series range. Designed to be as unobtrusive as a halogen light fitting, it delivers performance that belies its diminutive 127mm square footprint — thanks to KEF’s patented Uni-Q driver array, which places the 19mm aluminium dome tweeter at the acoustic centre of the 100mm polypropylene woofer.
Uni-Q Driver Array
KEF’s Uni-Q technology is the defining feature of the Ci100QS. By positioning the tweeter concentrically within the woofer cone, the two drivers behave as a single point source, eliminating the acoustic lobing and phase issues that occur when drivers are mounted separately. The result is exceptionally wide and consistent sound dispersion throughout the listening space, regardless of where the speaker is positioned in the ceiling. A tangerine waveguide further enhances high-frequency dispersion, extending the coverage angle to 125 degrees.
Installation & Construction
The Ci100QS features KEF’s Ultra-Thin Bezel (UTB) design, with the slimmest possible rim around the speaker face to minimise visual intrusion once installed. Installation is rapid — once the 112 x 112mm cut-out is made and the wire is run, the speaker clips into place in under two minutes using KEF’s proprietary dog-leg clamp system. The mounting depth is just 72mm, and it accommodates ceiling thicknesses from 6mm to 24mm.
The included magnetic grille attaches without tools and is paintable, allowing it to blend seamlessly with the surrounding ceiling. The grille can be easily removed for maintenance or repainting.
Weather Resistance
The Ci100QS carries an IP64 rating, meaning it is protected against splashing water from any direction. UV-protected materials, specialised plating, and powder-coated metalwork ensure the speaker withstands prolonged exposure to humidity, making it suitable for bathrooms, covered outdoor areas, pool rooms, and marine applications.
Also Available
A round version of this speaker, the Ci100QR, is also available for installations where a circular cut-out is preferred.
| Speaker Type | In-Ceiling (Square) |
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| Series | Soundlight Q Series |
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| Driver Configuration | 2-way Uni-Q |
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| Woofer | 100mm (4”) |
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| Tweeter | 19mm (0.75”) aluminium dome |
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| Frequency Response | 80Hz – 27kHz (±6dB) |
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| Crossover Frequency | 3kHz |
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| Impedance | 4 Ω |
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| Sensitivity | 88dB (2.83V/1m) |
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| Amplifier Power | 10 – 50W |
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| IP Rating | IP64 |
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| Overall Dimensions (H × W × D) | 127 × 127 × 76mm |
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| Cut-Out Dimensions | 112 × 112mm |
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| Mounting Depth | 72mm |
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| Ceiling Thickness | 6 – 24mm |
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| Weight | 0.67kg |
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| Grille | Magnetic, paintable |
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| Also Available As | Ci100QR (Round) |
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