I’m not going to call the DD-15 Plus the best sub ever, as I did with the original DD-15, but the fact that I considered doing so should tell you a lot. I doubt you’re going to find a subwoofer that delivers substantially more output or better sound quality that this one. I haven’t seen anything else that delivers a tuning/EQ capability that can match that of the DD-15 Plus.
That said, the appeal of the DD-15 Plus is limited. For the price of one of these, you could get two kick-ass 15-inch subs and an SMS-1. That way, you’d have much smoother response across a range of seating positions.
So who’s the DD-15 Plus for? The well-heeled audiophile or home theater enthusiast who wants just one really awesome, perfectly tuned subwoofer.
Frequency response
15 to 102 Hz ±3 dB
Bass output (CEA-2010 standard)
• Ultra-low bass (20-31.5 Hz) average: 118.3 dB
20 Hz 113.7 dB
25 Hz 118.7 dB
31.5 Hz 122.5 dB
• Low bass (40-63 Hz) average: 124.6 dB
40 Hz 124.6 dB
50 Hz 124.9 dB
63 Hz 124.2 dB
I measured the frequency response of the DD-15 Plus by close-miking it and running sinusoidal sweeps from my Clio FW. (I made all these measurements before I ran the Auto-EQ routine, to ensure that I wouldn’t be measuring the effects of the EQ.) The chart shown here is the result in Defeat mode without the crossover activated. Jazz mode measured exactly the same. The other modes all boosted output by about 2 dB overall. Rock mode introduced a slight additional boost of about 1 dB centered at 50 Hz. Theater mode’s additional boost was about 3 dB, centered at 37 Hz. Games model boosted at 60 Hz by about 3 dB.
I’m not going to cite a low-pass crossover function in dB/octave here because that slope is adjustable on this sub.
I performed the CEA-2010 output measurement in the Defeat (bypass) mode; measurements made in the Theater mode came within a fraction of a dB at most frequencies. (Again, these measurements were made before Auto-EQ was ever activated.) Output is excellent, averaging a brutal 124.6 dB in the low bass (40-63 Hz) octave and 118.3 dB in the ultra-low bass (20-31.5 Hz) octave. The closest I’ve measured using CEA-2010 is the Hsu VTF-15H, which hit 123.2 dB and 119.2 dB, respectively. So while the DD-15 Plus does offer loads of clean output, it’s not especially impressive on a dB-per-dollar basis.
#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?.