"As shared earlier, for larger spaces I had no initial joy matching passive dipole LF output to widebander amplitude so decided on an active bass system. I came across a 200-watt mono gain solution around a TI TPA 3255 chip which worked better than anything else I tried to activate this bass system. This becomes particularly salient for dipoles as cubic room volumes increase. If one remains below 30m², passive still works fine. My XO² filter/amp box does 200wpc in class D with dual-mono LF gain adjustments and low-pass adjustments from 40-200Hz, with recommended settings for our Vox3 and Vox5 clearly marked.

"On the back are RCA and XLR inputs with a loop-through for a second power amp to avoid needing a preamp with dual line outs. These RCA outputs have a +6dB gain switch. The two external power supplies for the XO² are 48VDC switch-mode types with GaNFets.

"The low pass slope to the bass arrays is a 12dB/oct. so 2nd-order type.

"Both 12-inch SB Acoustics woofers per channel run in parallel and are slightly modified to fit the enclosure. They have 16Ω voice coils so with cabling present a ~7.5Ω load, a bit less in the passive version.

"Our latest 18cm Envieé has a larger 70mm AlNiCo motor and 13Ω voice coil. It runs wide open and on the bottom naturally drops off quite steeply at ~150Hz. On top it starts its shallow acoustical roll-out at ~8kHz. I use a notch filter to address an 800-2'000Hz plateau. The ribbon on its transformer enters at ~8kHz on a single capacitor."

Whilst waiting on my post-show loaners, a quickie thought experiment. You attend a show small enough to cover all rooms in an hour, giving you plenty of time to return for lengthy seconds wherever you please. All rooms except one are poob—purveyors of omni bass. Only one sounds demonstrably cleaner and resolved across the bottom octaves. Regardless of personal taste about tonal balance, density/speed and other aspects, all attendees call that bass quality superior, period. Competing speaker manufacturers notice, too. One sends over his acoustic engineer in an attempt to crack the code. Regardless of successfully identified cause and effect, who realistically expects these other speaker houses to return to their factories with a revelation and plan for change?

If one has successfully promoted omni bass for decades and sold such speakers up to €200K—sealed or ported is immaterial—how to suddenly make an about-face only to declare that everything one did before was wrong? Børresen are currently the only ported brand I'm aware of which slowly rolls out folded-dipole bass systems. "We found a better way" is a gutsy admission to make. It's just not one I'd expect many to make. Instead, poob will continue to be the domestic default. With copious classic bass traps, it's certainly capable. Directional bass then is for those who want capability but no unsightly bass traps.

I should think that to be a large percentage of the overall audience. It just must know of a better way; then have sufficiently price-tiered options available to follow up with. Thought experiment over. But it explains why at least in our pages, mentions of RiPol or dipole bass are ongoing. If one has discovered a better way, wanting to share it is human nature.

Whilst head-on it doesn't look it, the Vox5 is a near full-range dipole once we factor in the sound|kaos scoop behind the 150Hz-8kHz widebander which adds itself atop the 3 bottom octaves of the dipole twin woofers. Only the upfiring ribbon tweeter identifies as a classic monopole though using the ceiling as a reflector actually works it omni like a Duevel. Again, this speaker isn't what it appears to be at first glance. We're back at the beginning: think different. Even the 5½-octave widebander applies that motto by running classically open like a purist Voxativ then adds a notch filter. Whilst the driver assemblage is that of a stocky three-way, the active bass filter makes it more of a two-way with integral subwoofer. Meanwhile the absence of hi/lo-pass filters on the widebander render it electrically other than a classic two-way monitor plus sub. And to reiterate what the above implied already, now Vox3 owners like Dawid Grzyb on staff have in the XO² the perfect solution to add a subwoofer to their 3-way compacts.

… to be continued…