In the updated series, most of the improvements are related to the speakers. The KEF Q150 and Q350 bookshelf models, Q550, Q950 and Q750 floor-standing models, as well as the Q650c center channel acoustics have undergone updates. The tweeters have received a damper tube, and the improved suspension and cone design of the woofers allows them to now deliver more bass at high volumes with less distortion.
In addition, like the previous generation of the Q range, the floorstanding speaker uses a passive radiator. This acoustic design has been known for a long time, but it was not very popular. However, modern materials allow better control of sound absorption and damping than before, so recently interest in it has increased. Ideally, such a radiator should combine the advantages of a bass reflex and a closed box.
The Uni-Q speaker unit seemed futuristic a few years ago, but today it is already perceived as a trademark of many KEF models. This concentric radiator has characteristics that are as close as possible to a point sound source, which favorably affects the size of the listening comfort zone and contributes to the accuracy of sound imaging.
The Q-series speakers from KEF in 2017 were equipped with optional decorative grills with magnets (decorative grills are now not included in the kit and are purchased for an additional fee).
KEF Q550 is the youngest and most affordable floor system from the new line. The outer classic rectangular shapes are immediately striking. And it’s not just a desire to return to a more strict style – for the same footprint, a simple shape gives an almost 30% gain in volume, which allows you to get deeper bass.
On the front of the KEF Q550 you will find woofer drivers, now reversed sphere diffusers made of aluminum-coated cellulose. The two-layer structure has high rigidity and low mass, and with effective suppression of internal resonances. There are three such 13-centimeter drivers in the column – one active and two passive, without a magnetic system and a voice coil. Acoustic design with the brand name ABR (Auxiliary Bass Radiator) required a lot of money, but it also gave clear advantages: faster response to the incoming signal compared to the phase inverter, the absence of turbulent overtones and a low resonant frequency of the system. All three heads are installed in an isolated volume and do not affect the operation of the Uni-Q coaxial radiator in the upper part of the housing.
This assembly has also been improved. It now has the same tweeter that was previously used only in the Reference series – with a more powerful magnet system and a rigid two-layer 25mm dome (in the older Q models they were smaller, 19mm in diameter). The tweeter is damped by the rear air duct, thereby reducing distortion and resonance. Extended dispersion is achieved thanks to the Crown Wave Guide acoustic lens and the Z-flex flat surround for the midrange. The photo shows the transverse ribs – they made it possible to reduce the height of the rubber ring and eliminate the barrier to the radiation of the tweeter.
The Uni-Q external cone is made of titanium-coated aluminum, the voice coil is wound with lightweight aluminum wire, and the magnet system is twice the mass of the previous generation drivers. A more accurate calculation of the drivers made it possible to simplify crossovers and, without increasing the cost of the structure, improve the quality of components – film capacitors and coreless coils.
The new KEF Q550 acoustics must be warmed up for at least an hour, during which time the characteristics of the woofer and passive radiators stabilize. The impression from the first minutes of listening is an amazing construction of the space. On most test recordings, the speakers literally dissolve in it, and the virtual images seem to exist on their own. True, for this you have to look for the optimal position of the speaker relative to the walls, since early reflections are also involved in the formation of the soundstage. Under optimal conditions, a real three-dimensional field is obtained with a background extending far beyond the speaker line. This is a clear advantage of the Uni-Q over traditional spaced-emitter designs. The test phonograms with drums and percussion recording on the disc made a very strong impression – each beat was clearly positioned in space,
In the updated series, most of the improvements concern the speakers. The tweeters have received a damper tube, and the improved suspension and cone design of the woofers allows them to now deliver more bass at high volumes with less distortion.
In addition, as in the previous generation of the Q range, most speakers (and in our system, all) use a passive radiator. Such acoustic design has been known for a long time, but it was not very popular. However, modern materials allow better control of sound absorption and damping than before, so recently interest in it has increased. Ideally, such a radiator should combine the advantages of a bass reflex and a closed box. Looking ahead, I will say that KEF was quite able to achieve this.
The Uni-Q speaker unit seemed futuristic a few years ago, but today it is already perceived as a trademark of many KEF models. This concentric radiator has characteristics that are as close as possible to a point sound source, which favorably affects the size of the listening comfort zone and contributes to the accuracy of sound imaging.
These properties are especially valuable for building a theater speaker system, but I would recommend assembling a set of speakers containing identical Uni-Q blocks – this approach will improve channel integration and effect movement across space will be smoother and more seamless.
