The Reference Brings Cutting Edge To Real Rooms

Today marks the introduction of five new models of The Reference series from KEF. Purely based on history, this is a significant occasion. The KEF Reference 105 was introduced in 1977 and Alan Sircom has said in The Illustrated History of High-End Audio that the Reference 105 “was arguably the most ambitious speaker anyone had built to date”. The Reference 105 incorporated a bevy of novel ideas including separate enclosures for each driver, minimized baffle width for low diffraction, time-alignment and unusual crossover circuit called Linkwitz-Riley after the inventors. In the 1980’s the Reference 103 was one of the great all-around speakers at a less than extreme price.

The new Reference series speakers aims to take KEF’s engineering prowess and take it to the next step, while at the same time designing speakers that fit well into modern living environments. The Series comprises five models with refreshingly simple monikers: The Reference 1 Meta, The Reference 2 Meta, The Reference 3 Meta, The Reference 4 Meta, and The Reference 5 Meta.

Despite that simplicity, there is a decoder ring that helps understand the line. The Reference 1, 3 and 5 are free-standing speakers, meant to be used as the left and right speakers in a stereo pair. The Reference 2 and 4 are designed to be used as any of Left, Center or Right speakers. That means an LCR system can be constructed from, say, Reference 1 for L/R and Reference 2 for center purposes. But an LCR array could also consist of Reference 2 speakers in each of the positions.

Free-Standing Versions

The Reference 1 Meta ($9,000 per pair) is a stand-mounted speaker, with a single ported 6.5” woofer. It uses the Uni-Q midrange/tweeter that is shared by all Reference speakers. The idea is that the Reference 1 is ideal for smaller rooms, where room gain would have speakers with more bass output overwhelm the balance.

The Reference 3 Meta ($15,000 per pair) is a floor-standing speaker, again with the Uni-Q midrange/tweeter but with two 6.5” ported woofers. It is intended for medium-sized rooms.

The Reference 5 Meta ($22,000 per pair) takes the woofer compliment up to four 6.5” woofers paired with the Uni-Q midrange/tweeter, and as you might expect fits in large rooms.

In all cases, The Reference series free-standing speakers assume enough living space to allow a setup with useful amounts of air around the speakers, so that their free-standing design can work to best effect.

Cabinet or Bookshelf Versions

The Reference 2 Meta ($6,000 each) and Reference 4 Meta ($8000 each) contemplate application in rooms where bookshelf or cabinet mounting is required, although they can also be used free-standing. Anyone who lives in a space with a single living area can appreciate that this application is sometimes necessary and that very few speakers are actually optimized for it. The drivers of the Reference 2 and 4 are symmetrically arranged so that they can be set up either vertically or horizontally (as in a center channel application) with no deleterious effects.

They also include adjustments for bass and treble balance to allow for differing proximity to the rear wall and for mounting behind a projection screen. The Reference 2 uses a sealed box and has a low frequency limit of about 46 Hz, and so users may want to pair it with a subwoofer for home theatre use. The Reference 4 is ported, and so will require adequate room for the port to function well. In return, it has low frequency limit of 33 Hz, which on music at least should satisfy many applications.

12^th Generation Uni-Q

The Uni-Q driver is a means of achieving time-aligned mid-range and treble for listeners in a variety of positions. At the same time, the Uni-Q array achieves broad, smooth off-axis response in a way that is difficult with separate drivers. This smoothness is critical to creating a realistic sense of space and accurate placement of instruments and voices.

The now-famous Uni-Q driver has been refined in many ways with, for example, a new motor system and spider to improve linearity of performance. One example of many parameters that have been made smoother across the speaker is shown in this inductance measurement of the new driver versus the old:

KEF has also developed an advanced decoupling system to ensure that vibrations are damped in a way that doesn’t radiate into the room. The goal is low distortion, particularly at high levels.

To take this distortion reduction a step further, KEF has applied its advanced meta-materials technology (hence the suffix on each model name). Meta-materials are new materials that do not exist in nature. In this case, KEF has designed a disc to go behind the mid-range/tweeter to absorb the back wave so that it does not reflect back though the cone or cabinet. The meta-material disc is tuned to a wide range of frequencies with variable length channels to make its impact spread across the wide range of frequencies where the Uni-Q driver is used.

Detail Improvement Enabled By Scientific Tools

The use of computer simulation, pioneered by KEF in the 1970’s and now vastly updated and enabled by hugely more power computers, is part of how so many design parameters were improved in concert with one another. Computer simulation, including Finite Element Analysis and Computational Fluid Dynamics, allowed KEF to evaluate a huge number of designs more quickly that would have been possible if full-scale product had to be constructed and tested. This approach allows more exotic options to be tested, whereas the expense of checking low-probability ideas often limits designers to conventional means.

The new The Reference series clearly pays homage to the ground-breaking Reference series speakers of decades past. In its additional effort to bring advanced engineering into the real world, it may constitute something of a breakthrough.

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