Velodyne makes excellent subwoofers make no mistake about it. They have been making subs since the early 1980s, longer than any other audio company. Velo's DD series pretty well set the stage for DSP controlled subs. I own a couple of Velos and am very happy with them, then again I own quite a few subs including Axioms that I enjoy.
However, I would pass on that particular Velo for different reasons than indicated above. Slot ports, such as those on these subs are notoriously noisy because of air turbulence from their sharp angled corners. But they are cheap to make and do provide extra output. If you compare it to the rounded vents on the 350 the Axiom will have far less chuffing at higher SPLs than a Velo DSP-10 or DSP-12 for that matter. The extension is also much better with the 350. No contest stick with the 350.
