Perhaps the best recent examples of that fact – besides the A2 that is – are the original Wilson Duette and the Focal Diablo Utopia. Both speakers were capable of a musical communication and coherence that shamed some of their larger, floorstanding, multi-way brethren – in no small part down to the inherent simplicity of a two-way crossover and the load that it presents the driving amplifier. Both were examples of the two-foot/two-way done better, with fancy cabinets, highly developed drivers and a lot of care expended on the crossover. The Duette in particular, caused a major rethink at Wilson, with a total overhaul of the range resulting, a switch in direction that started the company on the path its still following today. Sadly, that Duette is no more, sacrificed to the exigencies of the marketing imperative that feared it undermining the new, three-way, floorstanding and similarly priced Sabrina. Fortunately, that’s a fate that’s unlikely to befall the Alumine 2 – for reasons that it’s now time to discuss.
The other advantage that’s enjoyed by stand-mounted speakers over floorstanders of a similar price or internal volume is that the shorter length of their longest dimension makes for a more rigid enclosure with a higher resonant frequency. The A2 takes this to its logical extreme. Tall slim cabinets mean long, narrow panels and with circumferential braces adding to the cost and complexity of any cabinet, budget constraints make for a host of slim floorstanders where the cabinet’s potential to sing along constitute an almost choral tendency. Time to remind ourselves that the A2 was a proof of concept project – and one concept it was proving was the virtues of critical dimensions to cabinet behaviour. Thus, the quaintly squat A2 doesn’t just enjoy short panel; dimensions, those dimensions are chosen using ‘golden ratio’ proportions in order to spread the resonant signature of the structure as a whole.
Well-behaved cabinet panels are a good starting point, but where the A2 get’s really clever is in balancing its conflicting design requirements. As well as reducing the mechanical contribution of the cabinet, the designers wanted to maintain time and phase as well as impulse response: or to put it another way, the right amount of energy, arriving at the right time. The challenge is, that traditional speakers use internal wadding and heavy duty damping to kill the destructive contribution of their cabinets. Unfortunately, it also kills much of the dynamic range and slurs the musical energy generated by the speakers. Stenheim’s carefully proportioned cabinets reduce their sonic fingerprint, but they don’t eliminate it entirely. In order to avoid killing the musical energy generated by the drivers, the designers adopted sophisticated, low-volume, three-layer damping pads to control residual resonance within the cabinet walls, without impacting the enclosed air volume. Combine that with traditional, low-mass, organic driver diaphragms, modern magnets and motor assemblies, subtle horn-loading of the tweeter, reflex loading of the bass and a low-loss, phase coherent crossover and you’ve the makings of a speaker that is both more efficient and more musically communicative than its rather plain exterior suggests. Maybe it’s time to take a closer look…
