"Dear Srajan, Happy New Year with my best wishes to you, Ivette and that pretty cat of yours. I just checked on your site and saw three upcoming reviews where smaller widebanders combine with separate woofer enclosures. What an opportunity to sample the same basic concept executed three different ways! To be honest, I hadn't given this idea much thought but now spotting a relative mass sighting had me appreciate that it's rather alive and kicking. Do you expect to have all three sets in your house at the same time to conduct actual side-by-side comparisons? However that shakes out, I will be looking out for your findings. All the best." Magnus
Until Magnus pointed at it, I'd not noticed that within days, three previews for the sound|kaos Vox5, Voxativ Alberich2 and Zu Method system really went live to serve up three ways on how to mate small(er) widebanders to external bass modules. Independently, three designers concluded that giving up on the purist notion of a single driver covering all of the musical bandwidth swaps exhausting puritanism for proper pragmatism. Asking for help is no loss of face. It's just being practical.
Letting a single driver do it all can spawn constructions like the above and below German AER models. An expanding rear horn amplifies the driver's out-of-phase rear wave to add LF. Never mind dubious timing from phase shift and general lack of damping. To add the desired bass boost and extension requires big horns which the white model folds to reduce height whilst the red horn mouth could double as a baby's cradle. Rethm's original Saadhana segmented its rear horn to run a full circle before exiting. Voxativ's original Ampeggio folded its rear horn into two segments then faceted the second to open into a capacious horn mouth. Cube use TQWT short for tapered-quarter-wave-tube cabinets of considerable cubic volume. Zu use a mathematical model called Griewe loading to manipulate velocity/pressure values for extra bass.
In all instances, the demands for one cone to simultaneously do bass, midrange and treble out to at least 18kHz has typically meant a driver diameter between eight and ten inches plus a whizzer cone. With most players in this niche at it for ~2 decades already, it's interesting that many have finally capitulated to reality. Why not unburden the so-called widebander of about two octaves, in the process shrink it to perform better across the remaining bandwidth then bolt on active or passive woofers?
As Avantgarde's hybrid horns with active subs have shown, combining disparate modes of transport—ultra-efficient bullet trains on top, hard-working tractors on the bottom—can betray discontinuity. High-efficiency widebanders without horns are no different. To transmit no seam, any woofers hoping to blend should be different, too. At least that seems to be unofficial consensus when Rethm's isobaric active bass matches woofer and widebander diameters; when Cube's Lotus 10 runs the same cone size and materials for its auxiliary woofer and widebander; when Voxativ reaches for high-eff neodymium-powered woofers. Going generic seems declassé, mint your own the best solution.
How does my trio of contestants approach this? sound|kaos combine a 4" widebander with a Raal ribbon on top and dual 12" woofers loaded into an Axel Ridthaler-type dipole config called a Ripol. It's a folded open baffle with a dipole's lateral anti-phase cancellation, reduced output of the rear wave and very significant lowering of the woofers' resonant frequency. Its radiation is closer to cardioid than classic dipole, its principle that of a velocity converter not pressure generator. Voxativ's 5-inch widebander mates to a single Ripol 12er fronted by active plate electronics. Zu's front-ported Method monitor premiers their first 8-inch coax with compression throat tweeter down from their classic 10.3" platform whilst the matching Method sub is a single lightweight 15" paper cone firing forward then powered by Hypex Fusion amp with three DSP presets plus ability to let users change those profiles.
But the subtext is quite crystal. Shrinking the widebander to outsource 20-80Hz or thereabouts to specialized bass weaponry is the latest trend in this niche sector.
Thanks to Magnus for seeing it. On my wife's below desktop, it means that the forthcoming Vox5 will simply replace the steel stands and add two 12-inch woofers instead. That's a visually rather easier sell for a regular living room that doubles as listening den than AER's axjet. Even the above Lindemann Move/Groove combo is more conventional so friendly to off-duty civilians. Over 'n' out.
