KEF’s Ci160QS ceiling speakers is one of many designs that utilize their patented Uni-Q driver array. The speaker places the tweeter in the acoustic center of the bass/midrange cone (woofer) while allowing the larger driver to move freely around it. The woofer and tweeter design acts as a single, focused source of sound that is dispersed widely and evenly throughout the listening environment. This virtually eliminates the sweet spot effect and provides consistent high quality sound with properly placed speakers. The tweeter has a ‘tangerine’ waveguide that is said to provide exceptionally wide dispersion characteristics while protecting the driver from damage. KEF strategically places the woofer close to the front surface (forward mounting) to minimize diffraction and the effects of speaker placement. In addition, the new computer optimized trim ring is said to offer stunning midrange clarity and a more open and natural sound across a wider area. KEF Ci series UTB speakers feature a powder-coated grille with a proprietary plasticised additive, designed to resist corrosion making it ideal for humid environments such a bathrooms and pool areas. KEF’s new Ultra Thin Bezel (UTB) design offers the slimmest possible visible rim around the speaker.
The Ci160QS has a 6.5" (160mm) woofer and a 0.75" (19mm) Uni-Q tweeter with a crossover frequency set at 3.0kHz. The speakers have a nominal impedance of 8 ohms with an efficiency of 89 dB (measured at 1 Watt/1 meter). KEF recommends using an amplifier with a 10 to 125 watt rating. The Ci160QS frequency response
is 38Hz - 34kHz (±6dB) with an open-backed design.
KEF provides a Speaker Placement Tool application to help assist users in the placement and layout of KEF Ci loudspeakers. The tool was created by KEF UK engineering and is designed to graphically display the room sound coverage, recommended speaker layout, and speaker wiring diagrams. Users simply select their speaker model and enter their room dimensions (in meters or feet) along the desired number of speakers and the typical listening level. There are also options for listening positions (standing or seated), channels (mono or stereo), and room layout (rectangular or triangular). The last two options are based on the speaker model selected. Speaker impedance seen by the amplifier is calculated as well as the peak and average pink noise levels based on the configuration. Room layouts can be saved, printed, exported, and retrieved for future reference.
The design of the Ci160QS ceiling speakers makes them easy to install. The speaker required a square 7.5" x 7.5" cut into our 1/2-inch drywall, but could easily handle depths as much a 1-inch. Simply cut a square into the ceiling drywall using the template provided and make sure there is enough clearance around the perimeter to allow for mounting legs to extend. The gold-plated spring loaded speaker terminals posts accept wire as large as 12 gauge and allow for easy single-handed wire connections. Once the speaker is inserted into the square opening, simply tighten the screws and the mounting legs will automatically extend to hold the speaker in place from behind. The design distributes force evenly over the surface to prevent damage to the wall or ceiling. To remove the speaker, simply loosen the screws and the mounting arms retract allowing the speaker to move freely. The speaker grill is held in place with embedded magnetics, which hold the grille firmly in place. The final outside speaker dimensions are 8.75" x 8.75".
Ci160QS places the crossover components (resistors, capacitors, and inductors) on a curved-shaped printed circuit board (PCB), mounted inverted on a sturdy platform with heavy-duty standoffs behind the woofer. The design not only protects the crossover from potential damage during installation, but also adds rigidity to the speaker assembly. Separate speaker connections for the woofer and tweeter used by the crossover module are located on the woofer assembly. The heavier inductors are both bonded and strapped to prevent them from breaking loose from the PCB. The large spring loaded, color-coded speaker terminals used for connecting the speakers to the amplifier are on the same assembly, making the design modular.
In our installation, we used heavy 14-gauge
Tributaries wires to connect our Sonos ZP100 Zone Player to the speaker terminals. The ZP100 has a built-in amplifier rated at 50 watts per channel. Certainly not high powered, but very capable of driving these speakers to good listening levels.
We measured the impedance of the Ci160QS speakers using a Sencore SP295 Audio Analyzer across the full audio spectrum. The plot shows the impedance as a function of frequency so users can get a better idea of what the amplifier sees. The impedance was fairly flat, but did drop lower above 3kHz and reached a minimum impedance of 4 ohms at 20kHz. The peak was just over 10 ohms at around 2kHz. Regardless, any capable amplifier will have no problem driving these speakers with great results.
We listened to several types of music through these speakers with the Sonos Digital Music System providing the music and amplification. The Ci160QS
speakers provide excellent music reproduction with good off-axis high frequency response, making them ideal for ceiling installations. In fact, I prefer to listen them slightly off-axis as they have a smoother response in my opinion. I found them to be a little on the bright side when standing directly in front of the speakers. There are no user adjustments on the Ci160QS speakers, so you might have to rely on the playback system to provide tweaks to your equalization. Bass response on the Ci160QS speakers was good, especially at higher volume levels.
The KEF Ci160QS design is an excellent choice for small or large rooms using an array of speakers to support various configurations to maximize audio performance. The KEF Speaker Placement Tool will help you configure your system with predictable sound coverage and calculate amplifier loading to help you plan your room acoustics. While we only had two Ci160QS speakers on hand for the review, they provided excellent sound for the dollar. Installation is a breeze with the included template and built-in mounting legs. KEF has really made it easy for both professional installers as well as do-it-yourselfers. Priced with an MSRP of $249.99/each, the Ci160QS in-wall speakers are certainly affordable and come highly recommended.