KEF Ci200QSB-THX In-Ceiling Subwoofers – Pair

🧾 Overview

The KEF Ci200QSb-THX is a THX Certified Ultra in-wall / in-ceiling architectural subwoofer designed to deliver serious low-frequency impact without taking up any floor space. Used in passive mode it can reinforce the bass of KEF Ci speakers, and in active mode (with KEF KASA500) it can scale up to THX Select/Ultra certified performance in multi-sub installations.

✅ Key Features

• ✅ THX Certified Ultra2 / Select2 architecture for cinema-grade bass performance
• ✅ High-output 200 mm (8 in.) sub-bass driver for deep, punchy low-frequency reinforcement
• ✅ Dual operation: passive mode with internal crossover, or active mode with KEF KASA500 system amplifier
• ✅ Ultra-Thin Bezel (UTB) and magnetic, paintable grille for a clean “flush” finish
• ✅ Shallow mounting depth (101.6 mm) for easier installation in standard cavities
• ✅ Fast dogleg mounting system for secure installation on a wide range of surfaces
• ✅ Sold as a matched pair for symmetrical bass deployment and easier system planning

📊 Technical Specifications ▼

Parameter	Value
Product type	In-wall / in-ceiling passive/active architectural subwoofer (sold as pair)
THX certification	THX Certified Ultra (system performance scales to Select/Ultra specs depending on active configuration)
Driver	1 × 200 mm (8 in.) LF woofer (per unit)
Nominal impedance	6 Ω (Passive Mode, crossover “ON”)
Sensitivity	85 dB (2.83 V / 1 m, Passive Mode)
Crossover frequency	100 Hz (Passive Mode)
Frequency response	40 Hz – 100 Hz (Passive Mode); 18 Hz – 140 Hz (Active Mode with KASA500)
Recommended amplifier power	10–150 W (Passive Mode); KEF KASA500 required for Active Mode
Inputs / terminals	Speaker-level terminals (wired connection via external amplifier)
Wireless connectivity	Bluetooth / Wi-Fi: Not applicable
External dimensions (H × W × D)	273 × 273 × 106 mm (per unit)
Cut-out dimensions (H × W)	238 × 238 mm
Mounting depth from surface	101.6 mm
Mounting thickness	Min 6 mm / Max 40 mm
Optional rough-in frame	RIF200S
Net weight	3.3 kg (per unit)

📦 What’s in the Box

• 📦 2 × KEF Ci200QSb-THX in-wall / in-ceiling subwoofers
• 🧲 2 × Magnetic paintable grilles (Ultra-Thin Bezel design)
• 📄 Cut-out template (downloadable from KEF product page “Downloads”)
• 📖 Installation manual & setup documentation (downloadable from KEF product page “Downloads”)

🔄 Compatibility

Designed for custom-install home cinema and multiroom projects. Works with AV receivers and processors via an external subwoofer amplifier (speaker-level wiring from amp to subwoofer). In active mode it is intended to be driven by the KEF KASA500 System Amplifier; in passive mode it can be used with a conventional power amplifier within the recommended power range and crossed at 100 Hz.

📦✈️ Shipping & Returns

📦 Insured worldwide delivery
🔄 14-day return policy
🛡️ 2-year EU warranty

📝 Reviews

• “Great bass without floor space?” — Audioholics (Ci200QSb-THX / Ci200TRb Preview, Oct 24, 2016) :contentReference[oaicite:0]{index=0}
• “This sub is sold in pairs and can operate in passive or active mode.” — Sound & Vision (CEDIA 2015 coverage: “KEF Refines and Impresses”, Oct 19, 2015) :contentReference[oaicite:1]{index=1}
• “It’s 18Hz-140Hz in active mode with their amp.” — AVForums (discussion thread on KEF in-wall subs) :contentReference[oaicite:2]{index=2}

⚠️ Warning

⚠️ Warning: Installing these subs may cause sudden confidence in “invisible bass”, irrational satisfaction from perfectly flush grilles, and an uncontrollable urge to add “just one more pair” for THX Ultra bragging rights. You have been warned.

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