The drive unit line up reads more like a haul of loudspeakers. There are seven front-firing and two rear-firing drive units in each loudspeaker. Of these, the front and rear 25.4mm Version 5 Convergent Synergy soft-dome tweeter, and the front and rear 127mm pulp paper upper midrange units were designed specifically for the WAMM Master Chronosonic, while the 267mm and 318mm bass drivers were also designed for the WAMM Master Chronosonic, but the Alexx got them first. Only the pair of 178mm fabric lower midranges (used in seven other designs from the XLF onward) are not part of the WAMM design process. What’s more, treble, upper midrange pair, and lower midrange pair are housed in adjustable pods in a micrometer-precise framework. And it’s here where we get things wrong in audio. We glory in adjustable loudspeaker housings to help time-align the loudspeaker, but this seems slightly crazy if you think it through, because the slightest movement of your head relative to the time-aligned loudspeakers will throw everything out of balance. Instead, says Wilson through the medium of the WAMM Master Chronosonic, perhaps we should be looking at time alignment in terms of time coherence. This harks back to Wilson’s original patents on time alignment back in 1984, but these concepts remained largely unrealised in domestic loudspeakers until the arrival of products like the Sasha, Alexia, and especially the Alexx.
Our aural system is relatively insensitive to small changes in the time domain, and above 5kHz, our ears cannot detect timing-related issues less than about 10microseconds (µS). This is also one of those aspects of aural performance that does not decrease with age: our ears lose both high frequency performance and consistency with age, but our ability to determine time-delay errors is undimmed by maturity it seems. Given the speed of sound in air at around sea level, this relates to approximately 3.43mm. In other words, get the loudspeaker aligned so that the distance from speaker to ear and from ear to floor right with that kind of precision, and it will sound ‘time coherent’. Most loudspeakers get their time coherence right to within about 100µS, the WAMM Master Chronosonic gets to an impressive 2µS. Of course, this kind of precision requires two things; a loudspeaker capable of a significant amount of adjustment (and a rigid lock-down when adjustment is complete), and installers both trained and obsessive-compulsive enough to complete the installation process with a degree of absolute thoroughness.
The WAMM Master Chronosonic doesn’t just require a precise installation, it also requires careful selection and compensation for upstream electronics. Put simply, if you have 10µS sensitivity in-head, the loudspeaker is good for 100µS and the amplifier 50µS, the pinch-point is not the amplifier. But if the loudspeaker is capable of time-coherent precision down to 2µS, then the performance of the amplifier suddenly becomes a pinch-point. Wilson Audio has already started to analyse the ‘time profile’ of several amplifiers that might be used with the WAMM Master Chronosonic, with D’Agostino Momentum mono amps and the VTL Siegfried tube mono amps being the first candidates.