Alpine SWX-1243D – Subwoofer Review

The first gen Type-X 12" subwoofer from Alpine, reviewed in 2005, had our evaluators saying things like, "Alpine has done an incredible job in creating a wonderful sounding subwoofer." That wasn’t enough for the engineers though; they had to make it even better. Alpine improved the Type-X woofer in ’08. Cosmetically, it’s hard to distinguish any changes at all aside from the obvious difference in color of the two-piece, cast-aluminum frame—now a semi-gloss black. But dive deeper into the technical side of things and the real story unfolds.

One of the primary goals in reinventing the SWX 12 was to improve efficiency. Initiating this meant addressing the issue of weight, starting with the three-layer cone. Tipping its hat to the original, the new gen SWX uses a parabolic-shaped cone with a carbon-fiber layer out front and a Kevlar-reinforced paper layer at the rear. The big difference, however, is the core material in this sandwich that has changed from an aluminum honeycomb to Rohacell—essentially, a foamed acrylic polymer. This strong material is extremely lightweight, thus lowering the moving mass of the driver, and thereby improving efficiency. Rohacell also benefits the cone by adding more bonding surface area with the other layers (compared to the aluminum honeycomb), improving rigidity. Additional stiffening comes from Alpine’s force transfer assembly," an 8-armed injection-molded polycarbonate and glass fiber structure that supplies attachment and suppport to the rear of the cone and a collar at its base, which connects to the voice coil former.

The second step in bettering efficiency was to address the motor components. While the new structure still uses a three-magnet stack, most of the metal components have been altered to fit the larger 80mm (2.83"), six-layer dual voice coil (VC). Size is not the only thing that changed with the VC. Interestingly, three of the six winding layers reside inside the VC former while the other three wrap around the outside in a traditional manner. Dividing the layers up in this fashion helps maintain cool VC operating temperatures by doubling the wire surface area in contact with the surrounding air. The design also doubles the area in contact with the "Twin=Wall" aluminum former, the latter helping wick heat away. This is particularly important since the VC wire is now made of aluminum (instead of copper, as in the previous generation), which is less tolerant of heat than copper. While your first inclination may be to question this decision, it actually benefits the driver by lowering the mass of the moving parts. These design elements also allow the driver to maintain its impressive power handling numbers listed as 1,000 watts RMS and 3,000 watts peak.

The increase in VC size also required changes in the metal components of the motor structure. The most notable is the redesign of the Compound Radius Curve (CRC) pole piece. The pole piece is the magnetic return in the center of the VC that usually (and in the case of the SWX-1243D) contains the vent hole you see at the rear of the driver. At the top of the pole, the newly designed CRC helps smooth the air flow and focus it through the copper shorting ring and heatsink. More importantly, the shape of the CRC controls the flux fringe field—the dispersion of magnetic flux within the magnetic field. By changing its design, Alpine was able to extend the range of the magnetic flux, thus bettering the magnetic X-max over that of the mechanical X-max. This means that the VC will always stay within the magnetic gap, lowering distortion at high-power levels. It also increases the efficiency of the motor, and with efficiency you get better response and more output.

These improvements should go a long way in the perfromance of this driver, so let’s get to the good stuff.

Getting Ready
Normally, I prefer to test subwoofers in the recommeneded enclosures listed in the owner’s manual; but Alpine was up front in saying that the best performance would be achieved in a larger-than-recommended sealed enclosure nettting 1.5 ft3 (the manual recommends 0.65-1.25ft3). Per this recommendation, I built an enclosure from 3/4" MDF with a 1.5" faceplate and minimal polyfill inside. I inserted the thoughtful VC configruation jumpers in the proper slots to achieve a 2-ohm load and connected the 12-gauge speaker wire to the gold-plated brass block terminals (insulated by an injection-molded form) using the provided hex wrench to secure the set screw. The C-shaped rubber gasket stretched over the basket’s mounting flange provided a tight seal against he enclosure. Once screwed in place, a slick cosmetic rubber cover press fits on top of the gasket, hiding the screws altogether.

The enclsoure was placed in the rear cabin of my F150 and adjusted to the optimum postion. For this test, I installed a 2,200-watt Zapco C2K 9.0. After a little adjustment, the crossover was set to 70Hz at 12dB to achieve the best transition with my system’s midbass.

Listening

R&B
Usher Confessions

At "mega" volume, I released the pause button and secured myself for the powerful bass not that kicks off "Confessions". I actually repeated this scenario numerous times as I was impressed with how strong and natural the SWX went from 0-45Hz and back to 0Hz. The sharp punches that followed were snappy with an abrupt decay. Exactly as desired. It was almost as if a mule were kicking the back of my seat. However, I didn’t find the rendering of the staggered bass lines as spectacular. They just weren’t as distinguised as I’d like, with the lowest notes sounding too similar, and leaving the impression as if it weren’t extending low enough. But I later dispelled that inital impression by playing the following track, "Caught Up". Here the lowest notes came through with authority, but did seem to do better at moderate- to high-volume levels—at low volume it just wasn’t as articulare as it could have been. Score: 8/10

Jazz
Diana Krall "All or Nothing at All"

The scaling of the string bass in this track really works the crossover area between the midbass and subwoofer. It’s here that a system’s transition between the bass ranges is delineated. With the Alpine, there was absolutely no draw to the sub’s location—the bass seamlessly transitioned betweeen the front stage and the sub so well that I verified that the sub was actually playing. The bass stayed up front and well-focused throughout the entire track. Very ncie.

While listening to the timbre, I noticed a slight anomaly. At low-volume levels, the defining tones of the strings were less resolved that I like. However, goose the volume to medium and moderate levels and the SWX-1243D comes alive, providing a nice bit of resonance to the front end. Score: 9/10

Reggae
Ziggy Marley "Gone Away"

Overlapping bass lines can be troublesome for some speakers,. With this in mind, it’s easy to see why "Gone Away" can be a difficult track for subwoofers. The heavy electric bass guitar often dominates the track’s lower frequencies, overshadowing the drum beats.

Once again, I noticed that volume dictated the sub’s level of accuracy. While not bad at low levels, there was a definite improvement at moderate volumes—not uncommon on larger format subwoofers such as this, and nothing that would be discernable when placed hehind the back seat or at driving levels. Note shifts of the guitar were easily detectable and the drum was reasonably taut with a little power behind it.

As with Diana Krall, the transition from the midbass of the front stage and the subwoofer was remarkably smooth. The sub also maintained a good, complementary image that was up front with the rest of the system that never stepped out of place. Score: 8.5/10

Electronic
Techmaster P.E.B. "Bass Computer"
Power Supply "Bass Boom Bottom"

While re

arranging my music collection, I found some "real" bass CDs I thought were long lost. Back when bass was big and crusin’ was cool, these CDs got a lot of play by subwoofer-loaded ground shakers that could rattle your mirrors from 10-car lengths back. The label on Techmaster P.E.B. reads: "Caution" Ultra Low Bass May Damage Speakers," which may have carried some truth with subs of its time. Today’s drivers are far more advanced—but that didnt’ stop me from trying.

I first delved into Power Supply and pulled up the title track, "Bass Boom Bottom". This is an intense, electronically derived composition that has nearly constant bass the entire duration of the song. Hoping my electical system would hold up, I cranked the volume knob until the system reached the "neighbors are complaining" level. The Alpine woofer clearly had no problems with my action, as it stretched its surround to near max. Its output was quite spectacular—enough to make me surrender to the beast in the box.

With Techmaster came the ultra-low frequency goods. The lowest notes of Bass Comptuer" came through with authority, proving the SWX-1243D to be rather linear on the frequency scale. To that end, playing "Bass by Numbers" provided further prooof of its abilites. Driving these ultra-low frequencies at high volumes, I was highly impressed at the composure of the Alpine subwoofer. In short, it nvever seemed to display nonlinear behaviors or exhibit even the slightest hint of cone breakup. Its output (at comparable power levels) performance neared that of the ultra-impressive Critical Mass UL12 I had on hand for reference, but at a quarter the price. That of all things is pretty impressive in itself. Score: 9/10

Rock
Candlebox Candlebox

Most every track on Candlebox’s self-titled album is loaded with drum kicks, like every good rock album should be. The pace and ferocity of the hammer hitting, cracking the skin of the kick drum differs slightly between the tracks and when accompanied with a bass guitar the sub should be able to maintain good distinction.

I started off with "He Calls Home." In this slower-paced track the kicks should play through the accompanying bass guitar. Here the Alpine scored high with the kick drum very distinct as the snap of the hammer was presented with good attack and decay. The bass had a nice bit of resonance in its fundamental tones and again the SWX showed it can play nicely with the other speakers in the system.

Tracking back to "Don’t You," I paid close attention to the double kicks and how they differed from the individual beats. Again the Alpine proved to be fast and accurate, making it easy to detect changes in the amplitude of the drum kicks. Score: 9.5/10

Conclusion
Alpine’s latest iteration of the venerable Type-X sub is further proof that the company is serious about sound. While the improvements over the previous gen may go unseen, they’re a definite step in the right direction.

Alpine really has built an outstanding performer in this competitive price range-a musical subwoofer that is capable of turning out some serious SPL. Needless to say, I really enjoyed my time spent auditioning it. Regardless of the music genre, it was one of the most transparent subwoofers I’ve added into my system, and that goes a long way in terms of long-term listening enjoyment. If you have $500 for a subwoofer, check out this from Alpine.