If you’re thinking about skipping forward to read my complaints about this sub, don’t bother: I can’t find anything to complain about. The deep-bass extension was as good as I’ve heard; even the toughest deep-bass test I know of, the recording of the Saint-Säens “Organ Symphony” from the Boston Audio Society test disc, proved no challenge for the DD-15 Plus. Not only did the low notes shake my listening chair, I could feel them deep in my chest.
More important, though, was the effect of the Auto-EQ. From my listening chair, the bass sounded impressively even and smooth, with no notes emphasized and no notes lost in the acoustics of my room. Of course, this smoothness benefited the slick pop recordings I often use to test speakers — you know, Steely Dan, Toto, etc. — but it worked even better on headbanging rock tunes like “Love Removal Machine” from The Cult’s Electric CD. Anything with tight bass and kick drum sounded absolutely awesome through the DD-15 Plus when I had the Auto-EQ engaged.
Same goes for home theater stuff. The DD-15 Plus simply slammed out all my faves like the depth-charge scene from U-571 and the freeway pileup from Final Destination 2.
The only subwoofer I had around that could go cone-to-cone with the DD-15 Plus was the Hsu Research VTF-15H. Both are 15-inch subs, but there the similarity ends. The VTF-15H is larger, bulker, uglier, less powerful (350 watts RMS vs. 1,250 for the DD-15 Plus) and, at $879, vastly less expensive. The Hsu is also a ported model, while the Velodyne is a sealed box design. I compared them mostly with the Hsu’s ports plugged, which I prefer, and also with both ports open. I also compared the two with the DD-15 Plus in Defeat mode, which defeats the Auto-EQ feature, and with the Auto-EQ activated.
In terms of output, the two subs were closely matched. In my large listening room, both easily delivered all the bass I needed on every recording I played. The difference was in the sound quality. Even with Auto-EQ deactivated, the DD-15 Plus sounded a little tighter and more tuneful than the VTF-15H. With Auto-EQ activated, it wasn’t even close—the DD-15 Plus sounded much smoother. But you could always EQ the Hsu, perhaps using Velodyne’s own $499 SMS-1, which offers Digital Drive technology much like that in the DD-15 Plus.
#1 At frequencies below 100 Hz, the wavelength of sound exceeds 10 ft; even 1/4 wavelength exceeds 2-1/2 feet. There are no standing waves in a cabinet of the size of this subwoofer at its intended operating frequencies.
#2 Making the walls of a cabinet nonparallel does not eliminate standing waves, it only makes them more difficult to compute. If you doubt it, ask yourself: How parallel do the walls need to be for a cabinet to possess standing waves? If you still doubt, you can look it up: Richard Bolt, of Bolt, Beranek, and Newman fame, did the experiments for his PhD in 1939. His results are published in the Journal of the Acoustical Society of America.
Velodyne really missed the boat on the software, arbitrarily limiting the low pass filter to 40hz with the DD-15+. Those of us with full-range speakers that desire a bit of reinforcement in the deep bass are forced to compromise by this artificial limitation.
The prior DD-15's software DOES allow the low-pass filter to be user-set down to 15hz. It a shame that in order to get increased functionality, I HAVE TO GO BACKWARDS AND USE MY DD-15 BECAUSE I CAN'T GET VELODYNE TO PUT THE SAME FUNCTIONALITY INTO THE DD-15+. A SUPPOSEDLY MUCH MORE ADVANCED SUB.
I have owned Velodyne subs for over 20 years now and customer service has been great, UNTIL NOW. I AM NOW BEING TOLD THAT IN ORDER TO RESTORE THE FUNCTIONALITY THAT THEIR PRIOR PRODUCT HAD TO THE NEW (dd-15+) SUB THAT I ALSO OWN, IT WOULD TAKE "CUSTOM SOFTWARE", WHICH THEY DON'T DO. THEY HAVE KNOWN ABOUT THIS PROBLEM FOR OVER A YEAR NOW AND HAVE CHOSEN TO IGNORE IT. I DON'T DO "IGNORE" VERY WELL...
I AM VERY FRUSTRATED AND PISSED OFF AT VELODYNE FOR BEING BOTH IGNORANT AND NON-RESPONSIVE. IF YOU CAN'T PROPERLY SUPPORT YOUR PRODUCT, WHAT GOOD IS IT?.