Pros: Surprisingly good performance for the price, overall sound, construction
Cons: Styling, a little mud
A Little History
The Volfenhag ZX-4712 is a dual voice coil 12 car audio subwoofer. This sub was installed as part of a complete system in a 1999 Toyota Avalon. This sub is being fed by a Profile CA600M via 14awg speaker cable, receiving signals from an Alpine CDM-9827. All interconnects used are of decent quality, but no-names that came with the pro-Power amp kit.
This driver is relatively cheap and Volfenhag has only been around in any popular sense for several years, so this certainly would not have been my first choice when it came to car subs, but for the price I am really quite surprised by the ability of this subwoofer. The car has only factory damping, but about 22 square feet of Brown Bread sound damping was added to the trunk lid and floor. Brown Bread is almost identical to Dynamat except that the metal is slightly thinner, but it does a heck of a job. About three feet was used for the enclosure, but more on that later.
Install and Enclosure
The install of this subwoofer was about as easy as it can get. In the case of boxed subs, as opposed to form fitting units, install is only as complicated as lifting it into the trunk in most cases. The box I made for this application was covered with standard speaker carpet except for the bottom which I coated with a spray type damper and affixed a pair of strips of marine (as in water, not the soldiers) Velcro to for placement. The vast majority of sedan trunk floors will accommodate 30 or so pounds easily when the footprint is better than a foot squared. With this in mind, let me explain the Velcro.
This is a simple install trick that will make your life easier. Place Velcro on the bottom of your sub as well as the trunk floor to hold the sub in place during spirited or emergency driving. I tend to affix the strips, usually 2 wide strips, with the hooks facing down. I have found in my experience that this tends to last a little longer than the reverse and does less damage if removed and placed on the ground, i.e., linting. This may sound like an extreme step, but if your amps are simply mounted on trunk surfaces, having 35lbs. or so slide into them at high speed may change your mind when the music dies.
The enclosure for this particular sub was a simple cube with an interior volume of just short of one cubic foot. Rather than MDF, I used 1 medium grade plywood all around and utilized screws as well as epoxy for bonding. I did not stuff the box, but did use a layer of Brown Bread and sprayed-on butyl rubber to bring the box closer to dead. I chose not to use any internal bracing simply because this was neither a high dollar nor high fidelity install and I didnt feel like fabricating it. The connectors used were basic binding posts wired to the sub (wired for 2ohm) with 12awg cable.
I have known about Volfenhag for a while and have never been impressed about the way they present their product or the overall style of their subs. It always seemed to me that they seemed a little flashy, even, bling. I had seen the Volfenhag display at shows, but paid about as much attention as I did at the Audiobahn booth, none. I was blinded by sad style I guess, but the manufacture of these subs is actually fairly impressive, especially for the price paid over the net. This brand doesnt have a lot of backing yet and often shows up on the same pages as brands like Pyle and Pyramid, but I think that may change in the next few years if the quality stays up and the style is adjusted a bit.
From almost any picture off the web it appears that the sub basket is pressed steel when, in fact, it is thin cast aluminum. It seems sturdy enough and the overall weight of the driver itself lends some confidence to the product without a doubt. It is possible that this weight can simply be attributed to a cheaper magnet (larger) and the fact that Volfenhag chooses to dress the magnet in a pressed form with a ring of mesh doesnt help, but the cone is for real. The cone is aluminum attached to a surround that is not as large as they claim, but thick and rugged in appearance and feel and seems to do well as a mechanical damper.
There is much to be desired as far as the subs connectors. The connections are not exactly flimsy, but I really wonder whether even half azzed binding posts would have been that much more on the production side of things. The leads to the cone are plenty long and dont seem like a tear risk. The sub feature a continuous foam cover over the outer edge of the surround, though minimal, I could see this as a potential vibration damper, or at least more so than the sectional paper pieces so often seen on cheaper component subs. Overall, I would say that I am rather impressed with the fit and finish of this sub, it is certainly beefier than I expected.
With just the tweaking available to me via the head unit I was able to get very good punch out of it right off the bat. Forgoing loudness and focusing on level rather than boost, this sub is surprisingly punchy. It has such a broad range that it is a good idea to restrict it as much as possible to reduce muddiness as they try to push frequencies you dont require, but to some degree this is true with many of the cheaper subs on the market. I wouldnt be able to comment as to whether they achieve their claimed low end at any level, but I will say they took me by surprise at first. Putting in some 2pac first thing caught me a little off guard. Im not sure whether I wasnt expecting much from the amp, the speakers, or both, but it was an attention getter to say the least.
The integration with the rest of the system was very good, but I wouldnt say perfect. There were definitely some frequencies where the subs were trying to stomp on the primary speakers, but some additional adjustment got rid of much of it. The one thing I was not able to get rid of was some slight boomyness that was there from the word go. There are several things that could account for this, but in many applications I have dealt with, signal management is the best and quickest way to get rid of it. In this case, I think the receiver was plenty capable of that and the amp was set up well leaving only the sub as the weak link. Having built many a cabinet in my day, quite successfully I might add, I doubt the box was the culprit, but maybe thats arrogance.
Through more testing with a larger range of music including everything from Daft Punk to Morcheeba to Tantric the more impressed I got. I feel like this sub is lacking some of subtle dynamics found on some of the major name offerings I have installed, but it still has a strong presence and the ability to carry out the minor stuff effectively. I don't want to sound like I am holding this sub at the same level as a high end JBL or JL Audio, but certainly for the price this bad boy is worth a second look. I have never seen it in a retail store and I suspect that may have more to do with the actual manufacturer than brand support, but if you do most of your shopping online you should have no trouble finding numerous retailers quite quickly.
I list the numbers on this sub more as a point of reference than anything else. Although the raw numbers won't necessarily tell you good a given sub sounds, it should give you an idea what it capable of handling as well as how it compares to others at the same price point. I somehat doubt this sub does much around 20Hz, but thats what they claim.
General. . . . . 12" aluminum cone, rubber surround
Impedance. . . . dual 4ohm
Range. . . . . . 20Hz-1100Hz (infinite baffle-31Hz)
Sensistivity . . 89dB
Handling . . . . 250w/coil RMS, 500w/coil peak
This sub seems to be quite the bargain featuring not only decent manufacture, but rather decent sound as well and all that a low price. I have been less impressed by more expensive subs more than once, so running into a deal like this is pretty cool. As this sub will probably never be seen by anyone that ever hears them, looks are not a real concern, but if they are, little is necessary to match things up. At this point, I could see recommending this driver if money is a concern in almost any application, possibly against some Pioneer or Sony offerings in the same range. Overall, I am quite impressed with the performance of this sub and am a little sorry I didnt take them seriously at an earlier time.
For more information about this install or any others, including the Velcro thing, box building, or even basic wiring issues, please feel free to email me via the link on my page.