JL AUDIO GOTHAM V2 Dual 13.5-inch Sub

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Powered Subwoofer with Dual 13.5-inch Subwoofers, 4500 watts

Your first look will tell you that you are looking at something special... your first listen will confirm it beyond a shadow of a doubt.

The beauty of the Gotham® v2 extends well beyond its exotic design and exceptional craftsmanship, aiming right at the emotional core of musical and cinematic enjoyment. This is a subwoofer system with limits that exceed the needs of the typical home theater application, delivering a weight and integrity of reproduction that can only come from a system that is always in control. Its allure lies as much in its ability to convey subtleties as in its prodigious output capabilities. It is simply devastating.

A luxurious, handcrafted gloss-black finish is complemented by machined aluminum and stainless steel accents for a look and feel that fits perfectly with the finest home furnishings. More importantly, the beautiful cabinet houses a pair of JL Audio's highest-technology Subwoofers. When demanded by program material, the Gotham's prodigious switching amplifier can deliver 4500 watts of RMS power, to take full advantage of the twin drivers' four inches of peak-to-peak excursion capability. This ensures that the Gotham can breeze through material that makes other subwoofers go into clipping, limiting or distress.

A very complete set of signal processing features is easily accessible on the top surface of the Gotham. These include a highly flexible low-pass filter, variable phase, switchable polarity, e.l.f. trim and our powerful Digital Automatic Room Optimization (D.A.R.O.) system. A calibrated microphone is included for the D.A.R.O. system. Input connections are made via unbalanced RCA connections or balanced Neutrik® combo XLR/TRS jacks. Also included is an XLR output to connect a second Gotham® v2 as a slave unit.

Listening to a Gotham® v2 reveals an entirely new dimension of subwoofer performance... a dimension so satisfying that listening to lesser subwoofers will forever become an act of compromise.

Finish: Gloss Black, hand-finished to the highest furniture-grade standard.

Grille finish: Black fabric (separate grilles for drivers and controls)

Enclosure Construction: Fiberglass, 2-inch (52 mm) wall thickness

Detailed Information:

In typical listening spaces, subwoofer and listener placement have a profound effect on the accuracy of low-frequency reproduction. While we always recommend that you place your subwoofers in good-sounding locations, we know that these often can be impractical locations. In the real world, subwoofer placement almost always involves a compromise between sonic performance, practicality and aesthetics.

To face this dilemma head on, JL Audio subwoofer systems incorporate a clever piece of technology called Digital Automatic Room Optimization (D.A.R.O.). The D.A.R.O. system self-generates a series of calibration tones, measures the frequency response at the listening position, and automatically configures an 18-band, 1/6 octave equalizer for a flat end-result. The system effectively allows for smooth, well-balanced sub-bass from a variety of locations that would have been less than ideal without D.A.R.O.

To perform this audio magic, all you have to do is:

• Connect the included calibration microphone to the front panel of the subwoofer.
• Press the calibrate button on the front panel of the subwoofer.
• Hold the microphone at the primary listening position for about a minute.
• A few minutes later, you have completed this one-time setup routine.

You won't need a computer, spreadsheets or complex measurement equipment, and you won't need to navigate and manipulate complicated interfaces… D.A.R.O. is a fine example of technology in the service of man, if there ever was one.

Detailed Information:

Since 1997, JL Audio has been at the forefront of Finite Element Analysis-based modeling of loudspeaker motors and suspensions. This research is aimed at decoding what we refer to as the "Loudspeaker Genome"... a project aimed at understanding the true behavior of loudspeakers under power and in motion. A major component of this integrated system is DMA (Dynamic Motor Analysis). Starting with the 15W3 and the W7 Subwoofers in the late 1990's and early 2000's, DMA has played an important role in the design of all JL Audio woofers sold today, including our component woofers.

DMA is a Finite Element Analysis (FEA)-based system, meaning that it takes a large, complex problem, breaks it down into small solution elements for analysis and then assembles the data to form an accurate, "big-picture" solution. DMA's breakthrough is that it actually considers the effects of power through the coil as well as coil/cone position within the framework of a time-domain analysis. This gives us a highly accurate model of a speaker's actual behavior under real power, something that the traditional Thiele-Small models or other low power measurements cannot do. Because DMA does not rely on a steady-state model, it is able to consider shifts in the circuit elements being analyzed. These modeling routines are intense, requiring hours to run for a whole speaker.

DMA is able to analyze the real effects of fluctuating power and excursion upon the magnetic circuit of the motor, specifically the dynamic variations of the "fixed" magnetic field. This delivers intensely valuable information compared to traditional modeling, which assumes that the "fixed" field produced in the air gap by the magnet and the motor plates is unchanging. DMA not only shows that this "fixed" field changes in reaction to the magnetic field created by current flowing through the voice coil, but it helps our engineers arrive at motor solutions that minimize this instability. Analyzing this behavior is critical to understanding the distortion mechanisms of a speaker motor and sheds light on the aspects of motor design that determine truly linear behavior:

• Linear motor force over the speaker's operational excursion range
• Consistent motor force with both positive and negative current through the coil
• Consistent motor force at varying applied power levels

Our ability to fully analyze these aspects of motor behavior allows our transducer engineers to make critical adjustments to motor designs that result in extremely linear, highly stable dynamic loudspeaker motor systems.

The payoff is reduced distortion, improved transient performance and stellar sound quality.

Detailed Information:

One of the first things you notice about a W7 is that something is "missing"... the mounting flange. Of course, this is actually not the case. The mounting flange is simply hidden beneath the surround and is made accessible for mounting purposes by detaching the outer edge of the surround and moving the roll to the inside (a pretty neat little trick). Apart from the obvious benefits of amazing your friends as you pull the surround off your speaker, there is a serious technical issue that led us in this design direction: Effective Piston Area ("Sd"). This is essentially the speaker's "cylinder bore", to use an automotive engine analogy, and is calculated by measuring the diameter of the diaphragm including one-half of the surround roll-width. In other words, from the top-center of the surround on one side to top-center of the surround on the other side.

The displacement capability of a speaker is determined by this piston area times the speaker's excursion capability. Displacement of air is directly linked to output potential. Therefore, the more air a speaker can ultimately displace, the louder it can play. That being said, there is a big difference between piston area and excursion: piston area doesn't need power to make it happen. This means that by making a larger piston, you are directly improving displacement for a given amount of excursion and, therefore, making your speaker more efficient. This is not the only factor that governs efficiency, but it is a major one.

To make a speaker have more excursion capability not only requires a motor design that can deliver more stroke, but also requires a surround rugged enough to handle the demands of longer excursions and controlled enough to keep everything lined up properly. If the surround's roll-width is not adequately large, its behavior (compliance) is not linear over the useful stroke of the woofer and it is more likely to fatigue and fail. For this reason, speakers with longer excursion capability generally need larger surround rolls (we won't comment on the ones that use large rolls strictly for cosmetic effect).

The problem with big surrounds is that they begin to encroach on the effective piston area of the driver. For example, a typical 12-inch woofer with a medium-sized roll has an effective piston area of 81.52 square inches. Compare this to a fat-surround 12-inch woofer which has a piston area of 69.07 square inches (15.2 % less effective piston area than the medium-size roll.) To overcome this loss, the fat-surround woofer has to produce more excursion to displace the same air as the woofer with the medium surround (and will require more power to do so).

OverRoll™ technology neatly sidesteps this compromise by allowing us to make full use of the entire footprint of the speaker, placing the surround further to the outside than in a conventional woofer. This means that we can use a large roll for all its benefits without sacrificing cone area (in fact, the 12W7 has 1% more piston area than the medium-surround conventional woofer). By maximizing the effective piston/total footprint ratio, we can deliver more output for a given excursion and outside frame diameter. This means that the prodigious excursion advantage of the W7 can be put to full use enhancing output, rather than making up for lost piston area.

The technology also provides a geometry advantage on the outside edge of the surround roll, allowing for more linear operation. A further benefit is that the mounting holes are inherently sealed by the surround, resulting in an improved box seal.