The DSL Matterhorn, as per the video, is actually a very large tapped horn which means both sides of the woofer cones are used for pressurization, so that the back wave of the cones build up down through the expanding horn path to the bottom of the container, and from there the horn path goes into a 180 degree turn to continue back towards to the container opening where the combined wave from both sides synchronizes with the front wave of the woofers at the "mouth." This is not what the Borresen sub is doing (i.e.: it only uses the front wave of the cone, added to the fact that it’s not horn-loaded), and the "velocity" rethorics to me reads more into merely creating a combined pressurization through the slot at the front. Lot of yada yada and hifi sensationalism if you ask me, but I actually like the approach being the multitude of smaller woofers will combine and act like a single, larger woofer, which to me is preferred route vs. several smaller, and spread out woofers.