The most recent installation loudspeaker I reviewed was unusual for its significant depth. That was because the three way unit had its three drivers stacked, one in front of the other, bringing the depth to well over 180mm.

KEF’s Ci160TR speakers go to the other extreme. They make life easy if you have a very limited space in which to install the speakers since they require a mounting depth of just 36mm.

The Equipment

Now 36mm means that they ought to fit in all kinds of shallow partitions. Indeed, KEF mentions apartments and motor yachts. Likewise, in a conventional house they can be easily fitted into walls and thus do duty as surround rear speakers in addition to height ones. The grilles can be painted, of course.

So how is such a shallow depth achieved? These are two way units, and rather than having the tweeter concentrically placed in front of the bass/midrange, they are side by side. Which, when you think about it, is a touch ironic. In the home audio space KEF’s loudspeakers have in recent years been defined by variations on its Uni-Q point source designs, which feature a tweeter placed in the centre of a midrange or bass/midrange driver.

Even they would be too deep though.

So even though, installed with their grilles attached, these look like standard 200mm class ceiling speakers, the midrange/bass driver is a 115mm unit. It employs a flat diaphragm, built with materials to ensure its rigidity, rather than the more usual conical shape. Next to the midrange/bass is the tweeter. This has a vented voice coil behind the 25mm aluminium dome. It is fronted by a seven prong waveguide which KEF dubs ‘tangerine’, presumably because it looks somewhat like the segments of a citrus fruit.

The crossover between the two drivers is tuned for 1,700Hz, so the tweeter is doing a fair bit of the work.

Wiring is by means of spring loaded posts capable of holding a good thickness of cable quite securely. The circuit board for the crossover is oversized, effectively shielding the whole rear of the speaker from ceiling dust. The crossover itself appeared to be properly designed and robust, with at least three large coils, three large capacitors and two high power resistors visible in the space between the circuit board and the drivers.

Installation

The metal grille doesn’t encompass the whole front of the unit, but leaves a couple of millimetres of the bezel visible, slotting neatly into a ring-indent near the circumference. It is held in place magnetically. There is a thin layer of damping material behind the grill, and a ring around the edge that seems designed to mate it firmly to the main body of the speaker. Both grille and bezel are paintable.

The circumference of the whole thing is 235mm, while the required cut-out is a circle of 196mm. A cardboard template is of course provided. The speakers slipped easily into the specified holes without any overhanging bits to catch. They can then be secured with swing-out clamps, tightened from the front. There are three of these. If building materials permit, they can alternatively be secured using the four screw holes on the bezel.

The clamps were able to be unscrewed effectively from the front to permit removal, checking of cables and so on.

Performance

As usual I installed the speakers in my large box, imitating a fairly unloaded speaker environment. The immediate impression on playing music through them was of a severe lack of bass. That isn’t surprising, and of course KEF doesn’t claim anything much in the way of bass performance. But do note that there isn’t any significant mid-bass at all, and only a hint of upper bass.

Clearly, these speakers must be part of a system which includes bass from elsewhere, such as a subwoofer.

It would have been pointless doing listening tests without that bass because without a counterbalance in the lower frequencies, any speaker will sound tinny. So I coupled the speakers with a high quality subwoofer. Initially I set the crossover to 80Hz, but then I crept it up as the mid and upper bass remained somewhat recessed, eventually settling on 150Hz as providing a good balance.

I started with some Laura Marling, since her close-miked vocals and simple acoustic arrangements are remarkably revealing of system performance, and nearly magical in sound when the system just clicks.

The magic wasn’t quite there to the same extent as with my regular speakers (disclosure: KEF R300 compact speakers at the moment). But there were clear hints of it and excellent transparency. The only criticism I could lay upon the speaker, given its design goals, was the occasional whistle on her vocals, as though one frequency from the bright-ish microphone she was using was picked out and emphasised. (What this frequency might have been was not at all apparent in the measurements I conducted.)

Moving to something harder, I went for the DVD Audio stereo version of Led Zeppelin’s How The West Was Won, the live LA recordings from the early 1970s. John Bonham’s drums rang clearly out through the mix, even at high levels, while the whole thing remained nicely coherent. Of course the subwoofer was handling much of the energy from the bass and kick drum, as you expect in a proper installation.

I spent most of Since I’ve Been Loving You from this recording switching between ‘Direct’ and ‘Stereo’ on a home theatre receiver. The former switches out the subwoofer and has all the sound go to the main speakers. Even Robert Plant’s vocals benefited from having the subwoofer’s contribution, since without its lower frequencies it was a bit thin, and at high volume levels those upper frequencies were reduced in clarity by the speakers struggling with large quantities of low frequency energy with which they could do very little. Having the receiver re-route those low frequencies eliminated that.

The strings in classical music were nicely handled by the KEFs, clean and sweet, with no harshness.

All this is to say that if you install these speakers as height or rear surround, set the crossover appropriately (as indicated, 150Hz seems about right) and have your home theatre receiver’s automatic calibration routines adjust the frequency performance to match your other speakers, they’ll be doing to do a fine job.

Or if you’re going for a more ’pure’ system, without EQ, then once again set the crossover correctly and the naturally smooth balance of these speakers should allow them to work well with just about any high quality system.

A quick measurement confirmed my feeling that these speakers need bass support from larger speakers or a subwoofer. A very gentle roll-off commenced at around 220Hz. Very gentle indeed, to begin with, so that the output was down by 3dB at 160Hz and 6dB at 125Hz. And at 110dB – KEF’s bottom end specification – it was down by 10dB. That is within the ±6dB envelope which KEF specifies.

Measuring at 1m on axis the output was remarkably even from 190 through to 14,000Hz. Above that there were some wild swings, likely due to grille effects. (Could I measure without the grille? Yes, but what would be the point? You may choose to listen to your high fidelity separate loudspeakers sans grilles, but installation speakers will always have their grilles attached.) There was no hint of the crossover at 1,700Hz in the measurements.

Conclusion

If space isn’t a problem, then KEF have plenty of other installation speakers which offer a bit more in the way of bass. But if your installation locations do not offer much depth, the KEF Ci160TR speakers provide a way for high quality sound. Just remember that they will need accompanying speakers or subwoofer to deliver the bass for them.