Velodyne DD (Digital Drive) subwoofer repair (light).

Daddyjt · May 4

I titled this thread with the “light” because I took the easy way out and sent the plate amp to EBC for repair. For $400 shipped, they get it in tip top shape and do great work. I ran into a few other hurdles getting this unit back into service, and that’s what I’m going to expand on here.

If you’re unfamiliar with the DD series by Velodyne, let me just say that they are the most versatile, have the most prodigious output, and are the best looking subs that have ever been anywhere near my price range. I’ve even heard DD subs head to head with JL Fathoms, and the Velodyne went deeper and was WAY more versatile. As the old saying goes, when it comes to subwoofers there’s three things - small size, high (and deep) output, and affordability - but you can only have two. An affordable sub that goes deep is going to be huge… A small sub that is affordable is going to have limited output… Well, the DD subs by Velodyne are about as small as they can be based on their driver size, and have MASSIVE output - but they are most assuredly NOT affordable.

The versatility of the DD series comes from two things - one, they are “servo” subs, which means they have an accelerometer attached to the driver cone. This accelerometer tracks cone movement and compares it to the input signal roughly 6,000 times per second. Deviations are corrected in real time, which has an astounding impact on distortion. Typical high-end subs will see upwards of 30% distortion in the neighborhood of 20hz @ 100 db. A DD sub will be in the 2.5% distortion range. The second is an amazing onboard processor allowing adjustment of virtually every imaginable parameter, and also includes an 8 band parametric EQ, on-screen GUI, high quality microphone and a full function remote.

Original list on the DD18 was about $6,000. I purchased my DD12 that does duty in the family room 5.1 system for $4,000 in 2006. It’s in a great room that consists of the family room, dining room, kitchen and formal living room - roughly 1,000 square feet WITH 16’ vaulted ceilings (huge volume), and the DD12 is set at 60 out of 100 on volume to fill this space. My theater room that is 220 square feet with 9’ ceilings - and now has TWO DD18’s that I bought for $1,500 and $600 on the local classifieds. The $600 one I bought with a bad plate amp, which I sent to EBC and had repaired/refreshed for $400 - so I’m into a $6,000 sub for $1,000. The $1,500 one is the one I will be discussing in this thread.

Daddyjt · May 4

Anyway, I got the plate amp back, and got it installed as quickly as I could. There’s a lot to these things - the speaker wires to the woofer, the bus wire to the accelerometer, the bus wire to the front panel mic input, bus wire to front panel IR sensor, and bus wire to front panel light. So, all hooked up and I ran an input from my 2ch rig to it just to test function. Full stop. There’s a rattle/scrape/buzz sound. Shit. My first (and worst) thought was a blown voice coil on the 18” driver. Shit, shit, shit. Uniform pushing on the cone felt “scratchy”. Damn. So I uninstall the plate amp, flip the box over and then begin the process of removing the driver. The whole time I’m thinking “at least I have a backup plate amp (all DD series subs - 10”, 12”, 15” and 18” use the exact same plate amp) for my other 18” or my 12” should either of them fail.

pulling the driver is not easy - 16 Allen screws for the front bezel, then 6 more for the driver. THEN you have to get the driver out - and it’s MASSIVE - see pics. The voice coil is 5” in diameter, and a full 7” long. The magnet assembly is roughly 40lbs alone.

Once out of the enclosure, the cone-push test revealed no scratch or rub. None. Now I’m starting to be a bit hopeful! I inspected the cabinet for anything loose or with potential to rattle - nothing. Hmm…

Daddyjt · May 4

After a bit of brainstorming, I’m thinking either one of the FIVE different wires snaking through the cabinet was making contact with the back of the cone, OR one (or more) of the driver or bezel screws were loose. The IR sensor or the driver +/- speaker wires are the most likely culprits to contact the back of the cone. Therefor I wrapped both in bubble wrap and zip ties (positioning the zip ties so that they could not contact the metal of the basket and create any noise). I also took extra care in re-stuffing the damping material, and carefully tightened and torqued all driver and bezel screws.

I reassembled everything and fired it back up. Still a buzz - Damn… but wait - the noise I’m hearing is way off to my left. Way off. It’s actually my son’s cologne bottle on his vanity in his bathroom 15’ away! Whew. The sub sounds fantastic - and feels like an earthquake with a sweep tone from the Carver Reference disk. Mission accomplished - for the rest of the story, hit up the Chasing Bass thread.