- Written by Jim Clements
- Published on 22 December 2008
I remember marveling at the sound being produced by a pair of small bookshelf speakers during a recent visit to a local high-end dealer's shop. I asked the salesman, "The bass extension on these speakers is amazing for their small size. How do they do it?" "Technology" was his reply. I sat there stone faced for a second while the wheels turned. Great bass extension with useable output is still governed by the laws of Newtonian physics. Technology can't violate those laws. The designer must work within the framework of the laws to produce a design that will fulfill their objectives.
One critical parameter in subwoofer design is that you need to be able to move lots of air for relevant output in the lower registers. This means that the smaller the driver, the greater excursion you will need to achieve a given output goal. It's very difficult to increase a cone's excursion and still maintain low distortion and linear output. Furthermore, a smaller cabinet indicates a higher tuning frequency that would also work against the designer's overall objective. The Velodyne Optimum-12 subwoofer under review here aims to produce substantial output from a cabinet that's roughly the size of an old-school 17" CRT computer monitor. How did they do it? More importantly, did they pull it off? Please read on.
- Design: Sealed Enclosure
- Driver: 12" Forward Firing; 3" Voice Dual-wound Coil; 21.6 Pound Magnet
- Amplifier (Class D): 1,200 watts RMS; 2,400 watts Dynamic
- MFR: 22 Hz -120 Hz ± 3 dB)
- High Pass Crossover: 80 Hz (6 dB/octave)
- Low Pass Crossover: 40 Hz - 120 Hz (12 dB/Octave Initial, 24 dB/Octave Ultimate)
- Phase: 0°, 90°, 180°, 270°
- Digital EQ: Movies, Jazz/Classical, Rock/R&B and Games
- Dimensions: 15.4" H x 15" W x 16.25" D
- Weight: 40 Pounds
- Available in Black Lacquer or Cherry Veneer
- MSRP: $1,899
Velodyne Acoustics is so strongly associated with the powered subwoofer product category, that I was kind of surprised to learn they were "just" founded in 1983. I learned this fact as I prepared to review the newly-released Optimum-12. Velodyne produces powered and passive subwoofers at every conceivable price point. Whatever your bass production needs and budget are, odds are you can find a Velodyne model that can fill the bill. Their product ranges include large, small and mini freestanding subs as well as powered and passive in-wall models. They even make an active sub parametric equalizer with on-screen display capabilities, the SMS-1.
The Optimum-12 subwoofer is the largest and most expensive of 3 models in a new product line recently launched by Velodyne. The other models in the new line are the Optimum-8 and the Optimum-10. The Optimum models replaced the popular SPL series of subs and sit just below Velodyne's top of the line Digital Drive series of subs. Velodyne touts the Optimum subs as having "tiny cabinet dimensions". As mentioned earlier, the Optimum-12 is roughly the same size as a 17" CRT computer monitor (which is indeed compact), but I would not place it in the class of ultra compact woofers that have become quite popular over the last few years.
Design and Set-up
The Optimum 12 can be had in either of two finish options: hand-rubbed gloss black lacquer or real cherry veneer. My review sample was of the gloss black persuasion. It looked terrific and fit in nicely with the décor of my theater space. There is no up charge for the cherry veneer finish and I'm sure it's equally as nice as the black finish.
The sub comes with a remote control that controls all elements of the woofer's set-up and operation. This remote responded within a relatively narrow angle of incidence. The remote is very useful from the standpoint of being able to adjust the sub level on the fly, switch between different equalizer contours and cycle through the four available phase angles (0°, 90°, 180° and 270°). I really like having control over the phase angle while sitting in the theater space. I find that the differences between various phase settings can be very subtle and your aural memory doesn't always allow you to discern the different settings when you have to walk back and forth between the sub and your seating position. There is one other unique feature of the remote that I personally liked the most: it attaches to the back of the sub magnetically when not in use. How cool is that?
The Optimum-12 is equipped with a 1,200 watt Class "D" switching amplifier. This rating is on the basis of an RMS output. Velodyne claims that this amp can generate 2,400 watt peaks. No distortion specification is provided. Be that as it may, this is a lot of power and is one major key behind the sub's output and extension.
This sub comes equipped with a seven band graphic equalizer. There is no video or serial output that would allow the user to view or manipulate the settings. If you want to manually adjust things for yourself, then you will have to move up to Velodyne's Digital Drive models or purchase an outboard equalizer such as Velodyne's own SMS-1 both of which include outputs that allow the user complete control over the equalizer functionality.
The Optimum-12's equalizer is, therefore, fully automated. The user places the included mic at the seating position, presses a button on the remote and the woofer issues a series of sweep tones, measures the response and makes the appropriate corrections. The mic is a small, lightweight cylinder (about ¼" in diameter and ½" long). Its decent quality lead-in cable is flexible and easy to wind and unwind. The mic "stand" is a small, dense metallic pedestal. I wish it had a threaded fitting on the bottom so that it could be attached to a tripod. It did work competently when I placed it on top of the back cushion of my listening seat.
I must say that the equalizer in this sub is far more accomplished than the equalizer that's built into my receiver. It was able to flatten the response to a degree that has eluded me in the past. There is still a minor suck out at around 40 Hz but it is much less pronounced with the Velodyne than my reference system.
I would like to offer one more observation on the topic of equalizers. Being somewhat of a purist, I do not generally engage EQ's. As a point of fact, I run all my main channels un-EQ'd. But when it comes to subwoofers, I currently feel that equalizers are nearly essential to getting good bass response due to the realities of life. Most users don't have the flexibility to position their subs in the best place for smooth response. Instead, the woofer goes in the most convenient space in the room and equalization becomes a necessity to obtain the best performance. That's how it works for me; the sub goes in the front-left corner of my theater and I use the EQ to correct the tonal response.
The Optimum-12 is equipped with a two-character LED display. It's one of the really bright blue ones that may be distracting if not for the fact that it can be turned off. I turned it off. It does come on to confirm remote or hard button input. It also gives feedback in all areas of operation by way of abbreviated, logical messages.
The cabinet is sealed. All things being equal, a sealed cabinet design will start to roll off sooner than a bass reflex design. A sealed cabinet usually rolls off at 6 db/octave while a ported enclosure typically rolls off at 12 db/octave. Sealed enclosures also tend to produce bass that is perceived to be "tighter" and more in time with the music.
One of the first things I did after unboxing this sub was to perform the knuckle rap test which produced a hollow, ringing sound and caused me to furrow my brow just a little. According to Velodyne, a rigid cabinet is not a major design priority for the Optimum subs. They feel that the gently curved shape of the cabinet's side walls, along with the stresses induced by the cone's motion obviate the need to provide a more robust cabinet. While I have the intuitive sense that they are probably correct, most of what I have read would have me believe that a thin cabinet wall would produce its own distortion by way of propagating sympathetic vibrations into the listening space. Still, Velodyne is a highly respected sub design and manufacturing company with a stellar reputation. They obviously know what they are doing. The proof is in the pudding as they say. I did not hear any deleterious sounds from this sub that could be due to cabinet vibrations.
I am really impressed by the driver in this sub. It is a 12" nominal diameter driver with a generous surround. The cone is Kevlar-reinforced and looks like it could withstand a dynamite blast. The basket is cast, not forged. The dual-layer voice coil does its thing in a strong magnetic field courtesy of a massive 21.6 pound magnet structure. Velodyne does not spec the Xmax for their driver. I would venture that its maximum excursion spec is quite substantial.
The plastic grille sports a Velodyne logo at the bottom. The grille is affixed by way of de rigueur plastic nubs. The look is utilitarian. I wish Velodyne would go with a magnetic grille: I like the look with the grille off and the female parts of the mounting hardware affect the resultant look.
The Optimum-12 comes with installed rubber cones in lieu of the more typical metal cones or rubber feet.
My reference subwoofer system includes a Hsu Research VTF 3 subwoofer with a Turbo installed. I also have a Hsu Research mid bass module. The mid bass module handles the frequency range between 50 Hz – 80 Hz and the VTF 3 takes on all signals below 50 Hz. The VTF 3 by itself is at least twice the size of the Optimum-12. Both Hsu units have 12" drivers, ported enclosures and they are both driven by 350-watt BASH amplifiers. Current street price for all the Hsu Research elements in utilitarian black vinyl is currently $1,298, a little less than the going rate for an Optimum-12. All the main speakers in my system cross over at 80 Hz, honoring the THX spec.
"August Rush" is a delightful story about an orphan who uses his innate musical skills to locate and ultimately reunite with his birth parents. The protagonist, Evan Taylor a.k.a. August Rush, has one scene in which he plays a pipe organ. The bass lines came across powerfully with the Optimum-12. My reference sub, the Hsu Research combo, produced a more substantial foundation for this scene. In the movie's finale, the sound of the orchestra was positively riveting through the Optimum-12. The mid bass was very tight. The bass was tuneful while clearly preserving the waveforms of the various instruments. These characteristics made me feel that there was a certain organic nature to the sound.
The "Cars" Blu-Ray in multi channel PCM has a very complex mix that is immensely enjoyable. Once again, I noticed a certain organic quality in the bass during the California race scene. This organic characteristic of the Optimum-12 is most likely due to its low distortion and acoustic suspension (sealed) enclosure design. The pitch definition in the bass registers helped draw me into the movie. One more notable quality of the Optimum-12 that was really evident while auditioning this movie is that it was not as localizable as my Hsu Research combo. This was an all-around authoritative performance by the Optimum-12.
Next up was the Blu-Ray of Kung Fu Panda. Once again, the Optimum-12 didn't quite grab you by the seat of the pants to the degree that my Hsu Research combo can. Still, the Velodyne sub was well-integrated into the mix and could play very loud in my theater space. All in all, this movie was a dynamic roller-coaster ride that we all wanted to watch over again before the closing credits had finished running. I could happily live with this Velodyne sub and its tendency toward rollicking, white-knuckle performances!
My first impression of the Optimum-12 when listening to the SACD of the Allman Brothers Band's "Eat a Peach" album was that the bass seemed a little congested. I had set the EQ contour to Rock/R&B. I started experimenting with the various EQ contours that are embedded in the Velodyne's electronics. The four contours are labeled Movies, Jazz/Classical, Rock/R&B and Games. The Jazz setting is flat and does not have a subsonic filter. The other three modes have some sort of response contour and subsonic filter. I eventually left the sub on Jazz/Classical for most of my listening as it provided the best overall tonal balance and was the mode that provided the best integrated, least localizable performance. Once I had returned the EQ contour setting to Jazz, this Allman Brothers album really soared. No trace of congestion remained. The drum solo and bass chords on Mountain Jam (Track 4) had a realistic live concert sound to them. You could really hear the Fillmore East venue in the ambiance that was presented.
Mark Knoplfer's SACD of "Shangri-La" also gelled with the Optimum-12. The Velodyne thoroughly preserves the timing and rhythm of the music. I found myself turning up the volume to nearly irresponsible levels. The bass lines were in time with the music. Distortion levels from the Optimum-12 seemed to be about the same (or maybe a little less) than my Hsu Research combo. I was glad that the Optimum-12 includes protection circuitry that protects the sub without causing it to shut down. Thank you, Velodyne!
In general, my theater space comprises three parts. The main part is roughly 25' x 25' Almost a perfect square. The other two parts are two contiguous rooms that are connected to the main space by way of large openings. The acoustics of the space are generally very good, but the room does incorporate a large volume of air, presenting a potential source of strain on a subwoofer. To be honest, I was concerned that the Optimum-12 would have difficulty achieving reference levels in this space. Now that I have been able to spend some quality time with this sub, I am pleased to report that it handled just about everything I threw at it without obvious signs of strain. As long as the sub level was set to properly integrate with the rest of the program material, the sub went about its business without complaint unless I was attempting to play rock music at insane live concert levels. Not that I've ever been known to attempt a stunt like that!
The street price for the Optimum-12 will probably be around $1,500. At this price point, I would say it is a good value and worthy of consideration if you have a subwoofer budget of up to $2,500. I, for one, could happily live with an Optimum-12, even in my large theater.