Behind the mid/woofer sits a perforated HDF disc to "create a pressure environment bigger behind the driver than in the cabinet.  At low SPL, the driver doesn't see the cabinet at all. At higher SPL, the cabinet seems to get a bit smaller which improves control and power handling whilst the behavior of the ported alignment shifts to more of a sealed box. This speaker will play really loud yet its small driver is protected."

The crossover isn't a common parallel but series type invented by Bang & Olufsen in the 1970s. "This type maintains phase coherence across the crossover region since it doesn't treat its two drivers as separate. If for example the heavier cone's motion creates its own current, it will reflect into the tweeter to sound/behave like the dynamic driver at all SPL and through steep transients. The speaker stays fully awake at low listening levels and doesn't collapse at high SPL. The drawback of a series filter is twice the component cost as that of a parallel equivalent."

Based on an approach borrowed from marine sonar, Michael's analog dither modulates the noise floor. "At low frequencies, it injects random residuals of squares into the signal." These frequencies include the Schuman resonance and its harmonics like 55, 110 and 220Hz. These scalar fields combat the antenna effects of cables and are thus incorporated into the 01's filter network.

B-01 impedance plot above 6Ω. "The mid-frequency rise is due to the crossover where the two drivers share their current thus sum their impedance through the series crossover."

"The vanes across the port create small higher-pitched airflow vortexes, not one big noisy turbulence at the mouth of the port. Air turbulence noise is a huge problem for ventilated speaker designs. Our vanes along with semi-soft polyurethane foam lining inside the port effectively combat the dreaded port noise."

To recap, Børresen's B-01 incorporates a very low-inductance signal path, proprietary low-mass drivers with super-strong motors, optimized air flow, a low-turbulence port, a series xover with dither tech, RF/EMI-protected special hookup wiring and mechanical grounding to reduce electrical and mechanical noise. All of these design decisions pursue top speed, high dynamics and low distortion. Where and how would the Z1 tread more lightly to bag its savings? Would some of it not matter much—or at all—if one wasn't in the habit of playing as crazy loud and bassy as the B-01 can go? After all, it's the evil twins Loud and Low which cost the most money to be let safely run amok. If you don't know these blokes, less drastic measures will do.

Z1 with Aavik 180 separates and Ansuz cabling and power delivery.

If you're a B-range client, there's also the new Silver Supreme option. It replaces its drivers' massive copper rings with solid silver. Again relying on Aarhus University, each silver ring first cast at Børresen undergoes a 36-hour laboratory process to grow molecular skins of zirconium, tungsten and aluminium-titanium nitride. If you must ask about price—the silver B-01 adds €13'335 atop its €25'000 copper base tag—these won't be for you. In fact, if you calculate coin, a Z3 with dual 8" woofers will cost you less than a 4.8" two-way B-01 monitor with stand but obviously do lower louder bass. Choices. Having them is fab. Executing the right one could be tough? Said my contact Morten Thyrrestrup, "I love Heavy Metal and Rock and would probably get the Z3 over the B-01 for the extra fun factor even though the B-01 remains a more refined and resolved speaker."