I reviewed MartinLogan’s miniature two-way Motion 15 loudspeaker back in Issue 98 and it was quite the surprise package. Small but perfectly formed, it was the musical performance that really impressed: here was a hybrid AMT/dynamic speaker that really worked, a miniature that really delivered – a rare beast indeed. With the benefit of hindsight, perhaps its astonishingly capable performance shouldn’t have come as a surprise. After all, MartinLogan have been building hybrid designs for over 30 years and are also one of the few companies to crack the puzzle of actually delivering the potential cost/performance benefits of Chinese manufacturing (for the Motion series) with consistent quality. The Motion 15 stands as an impressive monument to the careful blending of Western expertise with the realities of global economics, a signpost to the future that can be enjoyed (and I do mean enjoyed) now. But the real question is, did MartinLogan – and the rest of us – simply get lucky with the Motion 15, or can they make lightning strike twice?
Outwardly, the 15’s larger sibling, the Motion 35XT looks all but identical: same flawless lacquer finish, same beautifully contoured and machined baffle, same distinctive, sloping topped cabinet and same combination of pleated AMT treble unit and neat, aluminium-coned mid-bass driver. In fact, short of sitting them side-by-side you’d be hard pressed to tell them apart. The 35XT might be a couple of inches taller and deeper as well as an inch wider, but it’s growth is proportional, meaning that the pleasingly balanced appearance remains almost unchanged. But appearances can be deceptive. As well as the increased cabinet dimensions (and internal volume) the 35XT sports a 165mm driver in place of the 15’s 133mm unit, as well as the larger XT tweeter. 32mm on the diameter of a bass-mid unit might not seem like much, but do the maths and you’ll realize that it all but doubles the swept area available. Combine that with the larger cabinet and you are looking at a handy increase in bass weight and extension – an area in which the 15 already excelled.
Of course, there’s no such thing as a free lunch, but when it comes to designing loudspeakers you don’t even get a half-empty dish of peanuts. Every design choice involves its own associated compromises. In the case of hybrid speakers that attempt to meld the virtues of two differing driver technologies, those compromises can be potentially fatal. The Motion 15’s performance is built around the successful integration of its two disparate drive units. But increase the diameter of the bass driver and you impair both its ability to reach up into the mid-band and its dispersion characteristics, key considerations when it comes to seamless integration. Simply stick the Motion 15’s tweeter into a bigger box with a bigger bass unit and the results would be predictably awful and disjointed. Which is exactly where the larger XT tweeter comes in, a unit with just over twice the radiating area of the one used in the Motion 15. That extra area allows it to reach lower down the range, in turn allowing the designer to roll it in at a low 2200Hz, rather than the 2700Hz used in the Motion 15. The end result is a loudspeaker that has almost identical sensitivity and electrical characteristics to the Motion 15, the same seamless integration and musical coherence but extends the –3dB point from 60Hz down to the magic 50Hz point. Why magic? Because that’s the point at which a speaker generates enough bottom end that it no longer sounds small or curtailed. Of course, extension and weight, body and presence aren’t givens, but at least the system has some meat to work with. The 35XT’s large, rear-facing port tells you that it’s bass is going to roll off pretty sharply, but it also hints at the substance it will deliver within its operating range and that’s exactly what you hear. The 15’s bass was quick, articulate, pitch secure, and rhythmically informative. The 35XT’s bottom end is all that, plus weighty, solid, and outrageously BIG – well, given the compact cabinet. Where the 15’s were a perfectly executed miniature, physically and musically, its bigger brother is a real room filler.