Subwoofer Reviews

The DN15 is powered by a 500-watt (1,500-watt peak) class-H digital amplifier with a 56-bit DSP that includes three custom EQ modes (Flat, Loud, and Deep). It has an Intelligent Phase Control with eight different options to optimize and align the subwoofer's phase with that of your main speakers. Along with the phase adjustment, rear-panel controls include volume, EQ, and low pass filter settings, and there's a button to toggle the sub's front LCD display on/off. A power switch offers three settings: Auto, On, and 12V. There are also IR and 12V trigger inputs, along with line-level stereo RCA and LFE inputs, and high-level speaker inputs. A small remote control is included that lets you control volume, phase, EQ, display, and low pass settings from the comfort of your couch as opposed to manually reaching behind the sub to make on-the-fly adjustments. Sadly, there's no parametric EQ or smartphone/tablet control app available to modify EQ outside of the three presets mentioned above.

Setup & Measurements
I ran the DN15 as a solo sub hooked up to the subwoofer output on my Trinnov Altitude16 preamp-processor, initially bypassing all the Trinnov's EQ to see how plug-and-play the Def Tech sub would be for the average user. One of the things I was curious about was how each of the three EQ modes would affect its output. Def Tech's description of these in its literature hit the nail on the head. Deep boosted output from about 17-23Hz by a couple dB over the Flat setting, while Loud had a similar effect in the 30-60Hz range. Flat was a good compromise between the other two, falling right in between. In the end, the one you select will come down to personal preference: If you expect to feel explosions, go for Deep, but if you're more of a music fan and want the thump of a kick-drum to be more pronounced, then Loud may be a better choice.

I sampled all three modes with various material and decided I liked the Flat best overall and used that when running the Calibration Wizard in my Trinnov pre/pro. After calibration, the bass response was more even and not so bloated. As you can see in the EQ graph, response came out relatively flat compared to no EQ being applied. If I owned this sub, I would spend a lot of time finding the perfect placement to minimize any negative reactions with my room, but overall, the results I got with it were more than satisfactory.

One thing I really liked about the DN15 was its Intelligent Phase Control. Using this was an improvement over most subs, which typically give you one of two choices: 0 or 180 degrees. But with the DN15, you get 0, 45, 90, 135, 180, -135, -90, and -45 degrees options. Setting phase using Room EQ Wizard (REW) software was a snap for me as well, and in less than three minutes I had found that 135 degrees was the perfect setting to pair the DN15 with my M&K S150 speakers. With that done, it was time to put this baby through its paces.

Performance
The DN15 proved to be a crowd-pleaser with movies. When watching discs with soundtracks that dip below 20Hz such as Pacific Rim, The Haunting, and The Polar Express (the train sequence), I was able to rattle the windows and let the neighbors know it was movie night. Playing the embassy attack scene from 13 Hours: The Secret Soldiers of Benghazi, the .50 caliber blast from the sniper rifle was loud, sharp, and impactful—just like it's supposed to be.

Another great demo to see how deep a sub can go is the "soften them up" scene from the Hacksaw Ridge Ultra HD Blu-ray. When the destroyer opens fire to shell the battlefield, multiple shots are fired in sequence. The DN15 was able to keep pace with the rapid fire, and it never sounded strained or overmatched. Well done, Def Tech!

I don't think of myself as an audiophile. I'm more of a podcast guy these days, and unless I'm reviewing a product, rarely listen to music anymore. I do have a standard stable of music tracks that I use for evaluation purposes, however. On example is "Mombasa" from the Inception soundtrack, which I use because it has a very fast tempo and requires the subwoofer to respond accordingly. Despite using a large 15-inch active driver, the DN15 was able to keep up with this challenging track and its bass response was clear and articulate. One caveat: When I bypassed the internal EQ in my Trinnov processor, the bass became a tad bloated and muddled with too much low output. EQ-ing this subwoofer is a must.

I had much the same experience with slower tracks such as Joss Stone's "Sleep Like a Child." With EQ enabled in my processor, each bass thump sounded clean, crisp, and solid. But when EQ was turned off, the low-end hung in the room much longer than necessary and lost its crisp impact. Turning down the subwoofer level a dB or two helped to eliminate bloat at the expense of bass output in the 40-60Hz range—not a great trade-off, in my opinion.

Conclusion
I enjoyed my time with Definitive Technology's Descend DN15 subwoofer and its performance met my expectations with only a few reservations. First, given the large enclosure, this sub is not for everyone. In my home, acceptance factor from my wife was low because even in our 15 x 18-foot theater, the DN15 was visually overpowering. It's just really big, and when placed along my front wall, jutted out a good 12 inches past my front speakers. Second, given the $1,800 price, I'm surprised there isn't a built-in PEQ (Parametric Equalizer). Granted, most A/V processors have their own built-in auto-EQ solutions such as Audyssey or Dirac, but other subwoofer brands offer apps that can store multiple custom EQs that the listener can switch to at their pleasure. Yes, the DN15 does offer three different EQ presets, but they are generic and not customized to your listening room.

The above caveats aside, I have no reservations recommending this subwoofer under the right circumstances: a very large room with no placement restrictions and an ability for the end-user to properly apply EQ.