This presentational difference is directly down to the Mezzo’s horn loaded low-frequencies. Look at the footprint of the Mezzo and it’s low-frequency cabinet is essentially T-shaped, the broad frontal aspect backed by shallow shoulders that quickly narrow to a tapering ‘body’ that extends 70mm/3” further back than the Duo GT. Like the other current Avantgarde speakers, the rear face of the cabinet consists of a full-height heat sink. The 1000W Class D amplifier that drives the twin 12” bass units is installed at the bottom of the cabinet. In front of that sit the two, vertically arranged XB12 bass drivers. These Avantgarde drivers are not your average 12” units. The long-fibre paper and carbon-fibre composite cones are attached to a massive 153mm/6” voice coil, suspended in a motor with magnets so strong that they generate an 11.5 Tesla flux density in its magnetic gap. In front of the drivers, extruded aluminium cheeks flare out to load and augment their output, accounting for the wide shoulders at the front of the cabinet. Clearly, the length of the horn is pretty short, meaning that the bass output is also heavily equalised (the Spacehorns are that size for a reason!) but even so, the acoustical advantage of horn loading the mid/upper bass in particular, will pay massive dividends in terms of dynamic continuity and integration with the midrange. I don’t know that extending the low-frequency baffle right up beyond the edge of the midrange horn also helps when it comes to system integration, but I’m betting that it does, visually and subliminally if nothing else…
The cabinet volume is reflex loaded by a pair of massive, downward firing ports, the internal mouths of which are arranged horizontally, precisely between the two drivers, creating a balanced acoustic load. This arrangement, combined with the horn loading, increases efficiency substantially (when compared to the single, forward firing port arrangement that loads the same driver/amp combination in the Duo GT). Given that both speakers offer the same 107dB overall system sensitivity, the implications are clear. This isn’t about how loud the speakler system will play. It’s about how much effort it takes to do it. The sigbnificantly more complex construction of the bass cabinet in the Mezzo allows it to match the bass output of the Duo GT at a given level while using around one quarter of the amplifier power. That gives the amp in the Mezzo a far easier ride and greater headroom, allowing its dynamic tracking to get far closer to the almost shockingly sudden response capabilities of the iTron amps, further aiding not just low-frequency quality but integration too.
Finger tip control…
When the Trio G3s first arrived, along with their massive, matching Spacehorns, the integration of satellites and subs was conducted using a fearsomely complex control programme loaded into a laptop. Undoubtedly powerful and effective, this was definitely a manufacturer/dealer function and might reasonably have been described as ‘user-hostile’. Considering that it can take days if not weeks to really dial in a sub or pair of sub-woofers, this was, by Avantgarde’s own admission, a far from ideal scenario. They subsequently came up with a far simpler, more intuitive and downloadable solution: one that owners can easily drive from their own PC or Mac laptop. I first came across the software package while reviewing the Uno SD, but the far more demanding context of the Mezzo set up really underlined just how easy to use and effective this control software really is.
