Sunday, March 16, 2008

Audiophilia: Velodyne DD-18 in the house

I used my annual bonus to finally complete my stereo system. I'd been holding off on buying a subwoofer until I had the money to spend and until I had a place where I could actually let a sub crank away without disturbing neighbors.

I'd originally decided to get the Velodyne DD-15 but saw a good deal on a DD-18--the monster big daddy of the line--and figured what the heck. It's in cherry and very nearly matches my B&W 702 mains.

With an 18" driver it is, not surprisingly, quite huge. More volume than a mini-fridge, but not quite as tall. Right now I basically never entertain guests, but when I do I'll have to figure out how to convey to people that it is not a bench and it is not a good place to rest drinks.

The coolest part about Velodyne's DD line is the built-in equalizer. It helps you figure out good sub placement and also allows you to tweak the sub's output curve to account for room/position acoustic problems (subs are notoriously difficult to acoustically integrate into a room).

The end results of the placement and equalization process are displayed at right. There's an expected rolloff below 32Hz. Otherwise the goal is to level the graph around 76dB to within a +/-3dB variation. I got pretty close; better than I thought I could do with my room situation. Notice the nasty suck out in my mains around 150Hz. Ug. I'm pretty sure the rolloff at the upper end is normal though.

I couldn't quite eliminate the peak around 35Hz--every time I did the sub would develop a kind of puckering noise at that point. If I eased off the EQ cut around that peak, the pucker went away and the sweep tone resumed its smoothness through that frequency. That being said, I do occasionally hear that pucker return during certain program material.

Unfortunately my Proceed PAV/PDSD preamp doesn't apply its crossover to the analog inputs. That means that my mains will play the sub's sweep tones at full range. As a work around I enabled the sub's crossover and fed its sweep tone output back into the sub's own input jack and then fed its crossed-over output to my preamp. Not ideal, but it gets us close enough.

Having leveled everything as well as I could, I recalibrated my speaker output levels and, for now, have the sub set at +9dB above "proper" calibration. Typical sub settings are +4 to +8dB so I'm only slightly above the upper end of the norm.

I'm fairly pleased. The 18" driver is of course way powerful when it needs to be but is way more than just a thump generator. The deep resonant notes of a cello integrate flawlessly with my mains, the sub subtly providing fullness and depth beneath the detail and texture. There is, as expected, no bloat or flabbiness whatsoever.

It's been a little difficult to find good test material; counter-intuitively the mark of a good sub is that it doesn't draw much attention to itself, despite its thunderous presence. "Us and Them" on Dark Side of the Moon is gloriously full and enveloping but the bass does not--nor should it--stand up and force you to take notice of it.

In a way it's almost anti-climactic for me--I want a sub there to articulate the low end, but I'm not such a bass nut that I was in agony all this time without a sub. My reaction has been a bit subdued. More of a "yep, it's doing its job, great" reaction than an "oh my god my whole musical experience is transformed."

Perhaps this has to do with my feeling that there is an occasional lack of attack in the sub. Sometimes I feel like the upper range of the sub/lower range of the mains should have more shape to it, more of a distinct leading edge. I'm not too worried about it though. More than anything, I've learned that I just haven't developed myself into a true sub/bass connosieur just yet.

I also think I need to play a bit with the "contour" setting. According to THX Ultra standards it should be fixed at 50, but I'm curious to see what effect it has on program material.

see: Stereophile: Velodyne Digital Drive DD-18 powered subwoofer review


Anonymous DigitalDon said...

I have a DD-18 as well and have found that the blend between main speakers and Sub, like many other system factors, depends on the main speakers bass output and pre-amp crossover point. I have sold B&W's for years and I am a big fan, however they are not known for their bass output. They really need mondo juice to get them to kick low.

Thu Apr 30, 09:31:00 PM CDT  

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