Velodyne Digital Drive 15, Absolute power

• The DD15 shows why Velodyne is considered the world's number one subwoofer specialist.

• Price: €5,000

• Specialists' rating: 5

• Text: Josep ARMENGOL

If you are a home theater enthusiast, you have surely heard of Velodyne: for almost three decades this manufacturer has specialized in active bass speakers, subwoofers, and its lineup includes models that have defined eras, such as the "1812", named after Tchaikovsky's overture, which demands a good capacity for bass impact if you want to reproduce the effect of the famous cannon shot in your living room...

After that famous model came the "Digital Drive" series, which owes its name to two factors: on the one hand, the use of Class D amplification (popularly but wrongly called digital) to reach levels above one kilowatt (1,000W), and on the other, its complex internal digital sound processing system, which includes a sophisticated equalization system, automated or fully configurable by hand, since the subwoofer itself includes everything needed for this: an input for a professional microphone and a video output for viewing the process (and its results) on screen.

Within this family there are several models, distinguished by the driver used: from 10 up to 18 inches! Our guest is the second largest, with a 15-inch driver, hence its name: DD15.

Description

Aesthetically it could not be more discreet, perhaps too much so considering its very high-end price, although the lacquer finish is impeccable: a near-cube about half a meter on each side, with a grille covering almost the entire front and a very comprehensive rear connection panel that also serves as the mounting for the internal amplification, as is normal in this type of unit. On removing the grille we come face to face with the 15-inch driver, and we immediately see that it works in a sealed enclosure, as there is no reflex port in the cabinet. This in principle limits volume and bass capability, but it allows a more linear frequency response and, above all, faster response, and given the size of the driver and the air it can pump, low frequencies will not be a problem. Velodyne tends to favor sealed enclosures in its models across all ranges, and this one is no exception.

On the rear panel we find every connection we could imagine: in fact, no other subwoofer offers so many options, and one in particular stands out for its presence here (and its absence on 99 percent of its rivals): the balanced line input (XLR connector). By design, this uses better shielding than traditional cables with RCA connections (which use the negative of the signal as ground or shield) and also eliminates stray noise that may creep in, by transmitting the signal in two opposite phases. Since this noise usually lies around the mains frequency (50Hz) and its first harmonics (100, 150, 200 Hz), and a subwoofer amplifies precisely these frequencies, you will understand why I insist on this point: because of all the times I have had to battle with a ground loop or stray noise that the subwoofer was amplifying.

Besides that balanced input, other notable features are a microphone input, also balanced (for using the professional microphone included with stand and cable), high-level (speaker) inputs, line inputs and outputs (playback inputs, outputs filtered at 80Hz and one dedicated to equalization, since it has an internal tone generator), and the video outputs (composite or S-VHS) for setup and equalization.

The remote control is noteworthy, very comprehensive since, beyond

the usual commands (volume, phase or some "equalizations" emphasizing certain frequencies), it lets us make optimum use of the internal equalization system. In the absence of a display (which the more recent DD "plus" models do have), we get confirmation of our commands through the illuminated logo using a series of clever codes: a volume of "24", for example, would be two long blinks and four short ones. Curious, and I would say more typical of a German product than an American one...

Test

Testing this subwoofer had two clearly distinct parts: first I tried it in a stereo system, for music, specifically the one in my basement with the monitors, where a bass boost is very welcome. Then came the test in the home theater room.

With the stereo system I spent quite a while "tinkering" with the equalization system: we must connect the subwoofer's output (EQ output) to our amplifier or preamp, place the microphone at the listening position and connect it to the subwoofer itself which, remember, contains the digital processing circuitry. The easy option is to let it perform a quick equalization: we will hear some test tones (repeated several times to ensure an accurate measurement), and once they are over we will already have a first (and quite good) approximation.

If we want to fine-tune or customize the setting, we will need to use the video connection: on screen we will have the table of available settings (extremely comprehensive) and a graphic representation of the frequency response. The idea is to "cross over" the subwoofer where we see (because... we can see it!) that our speakers begin to work; in the case of my monitors, a good sound level could already be seen from 60 Hz, that is, from that frequency upward they "work". If we crossed the subwoofer over at 80 Hz (they usually come set that way by default), we would have doubled-up level between 60 and 80 Hz, in other words an exaggerated mid-bass. While viewing the frequency response graph, we can use a parametric equalizer to make that response as linear as possible (I don't like the word "flat", although that is how the graph ends up looking), trying to cut peaks rather than fill dips (which requires more amplification). I managed to get an almost even response down to about 30 Hz, and subsequent checking with pure tones confirmed that the DD15 can make itself felt even at 20 and 25 Hz...

Once you know the equalization system, making adjustments or running tests and changes is very quick; it is just a pity that we cannot change the way the response graph is displayed: as it stands, it lacks some precision for better distinguishing the peaks due to room resonances (very pronounced) from those we can modify by changing the relative position of the speakers or the subwoofer itself. A good trick mentioned in the manual is to start by placing the Velodyne at the listening position and observing response graphs while moving the microphone around the room: wherever the response is most linear will be the best place for the subwoofer itself. The connection used in this case, after trying both available options (line output from the preamp, or high-level output from the amplifier), was the high-level one, which better preserves the balance achieved with equalization without having to keep adjusting the volume.

The effect of all this when you sit down to listen to music is simply exemplary: the system loses none of its previous qualities, in particular transparency and image precision, but clearly gains in bass extension by revealing the lowest octaves, and also in bass impact; there is also a curious effect of added "air" in the soundstage, which is more palpable with the subwoofer connected (it is easy to mute it from the remote control to compare). The Velodyne is also fast and will never lag behind the fingers on a double bass or the sticks on a drum kit, something important and by no means a given in a subwoofer: most, designed for movie effects, quickly succumb to the test of being installed in a decent stereo system, smearing the soundstage and literally giving you headaches.

Honoring Freddie Mercury on the anniversary of his death, I went through Queen's complete discography, and it was like having Roger Taylor right there with his drum kit. But don't think a bass speaker is only good for drums and bass: classical music, whether chamber or symphonic, also gains a dimension; as I said above, suddenly we seem to be breathing the same air as the performers, and if we mute the Velodyne we are left... without air.

These good results helped me haul the DD15 upstairs to test it in the home theater (don't try this without help, because its more than 40kg are no joke). Here, depending on the processor we have, the equalization options may not be so useful, since most modern receivers include their own measurement and equalization systems. But don't be fooled: precisely in the most critical band, the bass below about 200 Hz, there are still very few systems that really measure well and solve problems correctly.

We could start by leaving the subwoofer "direct" and carrying out a measurement and setup with the processor, but my advice would be to start with Velodyne's system, trying to get the subwoofer as well equalized as possible relative to the front speakers (using the receiver in stereo mode, as we did in the music system), and then let the processor measure and equalize: we will have prepared the ground and made its task easier, and the result will be better. On the other hand, it is a pity that most receivers have no balanced output for the bass channel to take advantage of that DD15 input, although fortunately I was able to.

Once it is "dialed in", brace yourself, because the first tests are not easily forgotten... Familiar scenes full of bass effects, where the LFE or ".1" channel is very present and active, take on a new dimension with a subwoofer of this caliber: I know this well, because I am lucky enough to have something similar (my 15-inch from B&W's 800 series), and no dedicated speaker I had tested until now had been up to its level, but this Velodyne is. To get straight to the point: the fusion scene in Spider-Man 2 is simply overwhelming, the impact of the light beams on the "tritium" takes your breath away, and the subsequent energy flow... it really seems as if our living room is about to collapse.

With soundtracks that use a low background tone, very common in "space" scenes, the tone is present and no details layered over it are lost, as happens with lesser subwoofers (where some notes blur others). A good example is the first scene of the third installment of Star Wars (Revenge of the Sith), when we see a great battle with drums in the background.

Nor can I fail to mention how it heightens the sense of claustrophobia in U-571, not only with the depth charges but in all the interior scenes, where a constant low tone (background machinery?) produces an effect similar to the one described when listening to pure music. And of course, how much it improves those brutal scenes of explosions or natural disasters (avalanches, floods...). Tremendous.

Conclusion

When someone has asked my advice about converting their stereo system for movies, I always give the same answer: if there are problems fitting in more speakers, it is better to give up on all but one, the bass speaker. A subwoofer will add a new dimension to movies, and we can also put it to good use for our music. In June 2009 I tested the small (but mighty) Velodyne SPL 1000 Ultra and said I was keen to try its famous big brothers in the Digital Drive series: that wish has come true, and the DD15 has not disappointed me. It is expensive, partly because of the internal equalization system (on its own it would cost more than a thousand euros in a separate box) and partly because of the quality of the driver used (a key component), but for someone with a high-end system this is the way to go. And for someone who aspires to one and is putting it together, take note, because choosing a subwoofer of this caliber can allow you to save a lot on the rest of the speakers (more than you invest in the bass unit) if you decide to set up a monitor/subwoofer system, especially considering how well processors and receivers are able to split frequencies and integrate all the speakers in the room perfectly. To both groups I enthusiastically recommend the DD15.

WE LIKE

-Very hard-hitting, extended bass: almost unrivaled for movies.

-It is fast, which makes it suitable as support for music.

-Ease of installation and versatility thanks to the microphone and the (on-screen) equalization system.

-Multi-function remote control.

-Very comprehensive connectivity, including an unusual but useful balanced XLR input.

COULD BE IMPROVED

-Display for volume and other functions (the new DD15+ model has one).

-Manual translated into Spanish.

-Very discreet, not very "showy" looks (for such a high-end product).

Velodyne Digital Drive 15, Absolute power

Specifications

Dedicated active subwoofer with a 15-inch active driver (12.7-inch piston, 3-inch dual tandem voice coil and 308-ounce magnet). Sealed enclosure. Anti-clipping circuit and woofer servo control with adjustable feedback. Line inputs (stereo RCA, mono XLR LFE) or speaker-level inputs (stereo binding posts); stereo line output for equalization. Programmable subsonic filter between 15 and 35 Hz. Variable low-pass filter from 15 to 199 Hz. 80 Hz, 6dB/octave high-pass filter. Frequency response: linear from 15 to 120 Hz +-3dB. Distortion below 1% THD. Adjustable phase and polarity. Automatic or manual equalization system, with measurement microphone (phantom power included). Remote control for: volume, manual equalization, standby, auto-equalization activation, "night" mode, turning off the multifunction indicator display. Automatic on/off function (signal sensing). Amplifier: Class D, 1,250W rated (3,000W peak). Dimensions (W x H x D) 457 x 512 x 460 mm. Gross weight 48 kg. Included accessories: IEC power cord (without ground); remote control with batteries, high-precision measurement microphone with stand and cable; line cable; comprehensive manual in English only.

Price: €5,000