Genelec The Ones - Forum

The culmination of years of R&D, these revolutionary new speakers offer performance way beyond what you’d expect from their size.

Over the 25 years or so that I’ve been reviewing Genelec products, I’ve always been impressed with the way this forward-looking company have maintained their edge by choosing different technological and ethical paths to most other monitor manufacturers. For example, sustainable production with minimal waste and low energy consumption has always been a company focus, and their products are designed for very long lives. On the technical side there are countless examples of innovative thinking, but perhaps one of the most relevant to this review was Genelec’s decision, in 1996, to construct speaker cabinets from recycled aluminium. This was revolutionary at the time, but has proved a hugely successful move.

With its unusually rounded, almost bulbous form, Genelec’s instantly recognisable cast-aluminium cabinet is the brainchild of a Finnish industrial designer called Harri Koskinen. But the project was about a lot more than just the visual aesthetics; it brought several important technical benefits, too. For a start, it heralded the integration of Genelec’s proprietary Directivity Control Waveguide (DCW), which shapes the baffle itself into optimised waveguides for the drivers. The rounded cabinet form also minimises edge-diffraction effects, a feature Genelec have christened the Minimum Diffraction Enclosure (MDE) concept. Moreover, the inherent strength of cast aluminium facilitates relatively thin cabinet wall thicknesses with little requirement for internal bracing, maximising the internal volume and minimising cabinet vibrations. Aluminium also provides excellent heat management for the electronics and drivers.

All of these benefits are present in the current 8000-series range of monitors, many of which also feature sophisticated DSP technology such as Genelec’s Loudspeaker Management (GLM) and Smart Active Monitor (SAM) systems, for remote control and automatic room-alignment EQ, respectively.

Finn Motor Skills

The subjects of this review are the two newest members of Genelec’s 8300-series monitors, which are the culmination of several revolutionary developments pioneered in earlier models. So, before describing the new monitors in detail, let me take you on a brief journey along the development timeline...

Most of the 8000-series monitors are two-way systems, with vertically aligned drivers in the familiar woofer-tweeter combination. There’s nothing wrong with that, of course — it’s a familiar setup for very good engineering and marketing reasons — but there are practical limits to the sound quality that can be achieved with this configuration, because each of the two drivers is required to deliver a linear performance over five or six octaves.

It is generally recognised that a higher level of performance can be obtained by employing a three-way architecture, which allows the bandwidth handled by each driver to be smaller. This approach brings a variety of benefits, including better matching of dispersion angles between drivers through the crossover regions, lower intermodulation distortion and better power handling. Genelec have long employed this approach very successfully in their larger monitors, but the extra cost, complexity and parts count makes it difficult to build a compact three-way monitor.

However, Genelec solved that problem in 2010 with the launch of their 8260A model, reviewed in SOS January 2011. Although this looks much like all the other 8000-series speakers, it is actually an ingenious three-way monitor featuring a brilliantly conceived dual-coaxial tweeter/mid-range unit. It took the company three years to perfect this unique dual-coaxial driver, in which a centrally mounted 20mm (0.75-inch) aluminium tweeter is integrated seamlessly with a 130mm (five-inch) mid-range driver, the latter’s cone and inner suspension forming a cohesive waveguide structure.

To The Point

Dual-concentric or coaxial drivers are not new, of course, and the roots of the concept can be traced back to the early 1940s — but although it’s an attractive notion for speaker designers because it brings a number of worthwhile benefits, it is not an easy configuration to master in the engineering sense. One of the key benefits is that the sound of both drivers emanates from a single point rather than from an array of separate drivers spread out across the baffle.

Generating sound from a point source inherently provides a sharper and more stable stereo image with a larger listening ‘sweet spot’, and it is thought this arrangement reduces listener fatigue because the source location remains constant regardless of any head movements from the listener — something which may not be the case with more traditional speaker designs.

It also has the advantage that the speaker’s off-axis sound projection remains a lot more consistent across the frequency spectrum than is usually possible with spaced drivers. Loudspeaker specifications usually focus on the on-axis frequency response, but actually the off-axis response is just as important and explains why different monitors sound so different in the same room, even though their on-axis responses might appear identical. The fact is that most of the sound energy within a listening room comes from the speaker’s off-axis sound reflected from the room’s boundaries; if the off-axis response is very uneven, the reflected in-room sound will be tonally coloured and that will affect our perception of the speaker as a whole.

Historically, the earliest dual-concentric loudspeaker systems evolved as full-range two-way configurations, integrating a tweeter within a woofer in some way. Some designs suspended the tweeter in front of the woofer, while others mounted the tweeter behind it, ‘speaking’ through a horn passing through the centre of the woofer’s voice coil. Later, the introduction of more powerful magnetic materials made it possible to build high-efficiency tweeters compact enough to sit directly within the voice coil of a woofer. However, one problem commonly found with this arrangement is called ‘Doppler distortion’, where the wavefronts produced by the tweeter are essentially modulated by the independent and relatively large movement of the woofer’s cone. In effect, the HF wavefronts get an extra unwanted ‘push’ from the woofer, altering the speed of the radiating sound wave and creating small Doppler shifts: a form of intermodulation distortion that manifests itself as tiny pitch variations.

Genelec’s dual-concentric design stems from original research dating back to the 1990s, but the specific development of the coaxial driver employed in the 8260A started in 2007, and integrates a compact tweeter with a five-inch mid-range unit. This configuration all but eradicates the Doppler distortion problem and, as there is no physical gap between the tweeter and mid-range diaphragms, there is no discontinuity for the radiating wavefronts either. Also, the shape of the mid-range cone acts as a waveguide for the tweeter, helping to match their dispersion through the crossover region.

However, although Genelec’s dual-concentric mid-range/tweeter design is both innovative and superbly engineered, and while the complete Genelec 8260A is a very high-quality, three-way monitoring system, the overall implementation can hardly be described as either compact or a point-source configuration — not when its beefy 10-inch woofer sits well below the integrated mid-range/tweeter...

The First One

This point-source conundrum was eventually resolved four years later when, in 2014, Genelec launched the improbably cycloptic 8351A monitor speaker. I remember clearly the first time I saw this uniquely styled monitor; it was at the AES Convention in Los Angeles in the Autumn of 2014, and it was quite a shock because the 8351A looked like nothing that had ever gone before! I even wrote an essay on the history of this company at university (instead of buy pre written essays) . My mind contemplated the possibilities: some weirdly demonic creation of a wild-eyed Finnish scientist unhinged by the profound lack of sunlight in his native land and fuelled by an excess of Olvi beer? An eerie genetic experiment involving an 8000-series monitor and an Auratone maybe?

I’m blaming such uncharacteristic flights of fancy on jet lag and a low blood-sugar level... Thankfully, my senses quickly returned after I settled into a comfy seat in Genelec’s demo room to hear the 8351, whereupon it became immediately obvious that this was something quite special: a truly compact nearfield monitor,with remarkable bass extension, pin-sharp imaging, and the kind of mid-range resolution and clarity that only a good three-way design can deliver.

You can read a comprehensive review of this genuinely ground-breaking monitor speaker by my colleague Bob Thomas in SOS August 2015, but perhaps his concluding summary really says all that needs to be said: “By any measure, the 8351A achieves a level of performance that more than justifies its price. Its outstanding stereo imagery, clarity, resolution and transparency together with its transient delivery, bass detail and extension prove, to my ears, that this innovative three-way, coaxial monitor design really delivers the goods.” I couldn’t have said it any better myself!

In brief, this revolutionary design places the dual-concentric tweeter/mid-range unit from the 8260A slap-bang in the centre of the baffle, the whole of which is shaped to serve as a waveguide. The low end is generated by a pair of bespoke bass drivers which have an oval or ‘race-track’ shape — their actual measurements being 8.5 inches wide by four inches high. These are mounted behind the main baffle, directly above and below the dual-concentric unit, with their sound exiting through crescent-shaped slots at the top and bottom of the baffle (as well as via a rear-panel reflex port) in such a way as to generate a circular wavefront emanating from the same acoustic centre as the coaxial driver.

This most ingenious and innovative arrangement establishes the highly desirable point-source principle across the entire audio spectrum in a really elegant way, and by employing the whole of the front baffle as a waveguide for the mid-range/tweeter, the directivity is controlled to a much lower frequency than is possible in conventional designs, where much of the baffle is occupied by a large bass driver. The 8351A really is a marvel of advanced engineering and imaginative packaging and, while the visual aesthetic takes some getting used to, the sound quality is quite remarkable.

The point-source speaker brings with it many practical benefits. One of the perennial ‘issues’ I encounter in project and professional studios alike is the fashion for placing traditional monitors, with vertically aligned drivers, on their sides. This ‘landscape’ arrangement causes several problems, starting with the fact that the frequency response of the monitors throughout the critical crossover region (which typically coincides with the vocal range) changes dramatically with small lateral movements of the listener due to comb-filtering effects from the varying distance between the ear and each driver. The precision and stability of the stereo imaging is also degraded significantly, and the HF dispersion is likely to be considerably narrower than the designer intended. In short, this positioning seriously compromises the monitor’s performance.

However, this problem doesn’t exist at all for the Genelec 8351A, because it behaves as a point-source speaker. Highs, mids and lows all effectively radiate from the exact centre of the baffle, and so the performance and frequency response are essentially unchanged whether it is used in portrait or landscape orientations; there can be no interference effects between the drivers to degrade the sound quality or stereo imaging for off-axis listeners. To facilitate landscape or portrait orientations, the familiar Iso-Pod stand can be attached either to the short or long sides.

Up Close & Personal

Another significant advantage of the point-source design is that the monitor speaker can be positioned much closer to the listener than is possible with a conventional speaker of similar size. In a conventional design, with vertically spaced drivers, the listener has to be a certain minimum distance away from the baffle in order for the sounds from each driver to merge correctly. Again, this is not the case for the 8351A because the coaxial mid-range/tweeter driver and the symmetrical coincident wavefront radiated by the twin woofers ensures that their relative balance and phase relationships remain unchanged almost regardless of the listener’s proximity.

Genelec state that the minimum listening distance for the 8351As is 0.4m, and to put that in context, the minimum listening distance for the equivalent-sized 8050 two-way monitor is 0.7m — nearly twice as far! The ability to work in the ultra-nearfield can be hugely advantageous when the listening room’s acoustics are sub-optimal. Nearfield listening inherently reduces the significance of room reflections, and the closer you can get to the monitors, the less the room’s acoustics matter!

Physically, the 8351A is quite large, at 452mm in height, and inevitably, many high-end customers requested smaller models with the same three-way point-source technology, but it wasn’t a simple case of just scaling everything down a bit! We’ve had to wait until the start of May this year for Genelec to perfect a smaller sibling — only to discover that the Finnish boffins have created not one, but two smaller versions.