12-inch (300 mm) Marine Subwoofer Driver, Gloss White Trim Ring, Gloss White Classic Grille, 4 Ω
M7 12-inch Marine Subwoofer for Infinite-Baffle Use (600 W, 4 Ω) – Gloss White Trim Ring, Gloss White Classic Grille
Engineered as the reference standard for marine subwoofer performance, the M7-12IB is capable of producing staggering amounts of jaw-dropping bass in infinite-baffle applications.
Built to withstand real-world marine duty, this M7-12IB is designed to operate without a dedicated enclosure. It boasts a monstrous 4-inch voice coil and rugged suspension system to deliver outstanding linear excursion for high output and power handling.
M7-12IB is best used with amplifier power in the 200W – 600W range and is optimized to operate with a large volume of air behind it (at least 3 cu. ft. / 84.95 l).
Like all JL Audio marine speakers, this driver is built to withstand a real saltwater marine environment and deliver years of listening enjoyment.
|Continuous Power Handling (RMS)||600 W|
|Nominal Impedance (Znom)||4 Ω|
|Free Air Resonance (Fs)||35.34 Hz|
|Electrical “Q” (Qes)||0.856|
|Mechanical “Q” (Qms)||10.389|
|Total Speaker “Q” (Qts)||0.791|
|Equivalent Compliance (Vas)||1.99 cu ft / 56.35 L|
|One-Way Linear Excursion (Xmax)*||0.73 in / 18.5 mm|
|Reference Efficiency (no)||0.28%|
|Efficiency (1 W / 1 m)**||86.7 dB SPL|
|Effective Piston Area (Sd)||80.54 sq in / 0.052 sq m|
|DC Resistance (Re)||3.543 Ω|
|* Xmax specifications are derived via one-way voice coil overhang method with no correction factors applied.
** Efficiency (1 W / 1 m) is not an accurate indicator of a subwoofer’s output capability and should not be used as a comparison to other subwoofers to determine which one is “louder”.
|Nominal Diameter||12.00 in / 300 mm|
|Overall Diameter (A)||14.00 in / 356 mm|
|Bolt Hole Circle Diameter (B)||12.813 in / 325 mm|
|Frontal Grilles Protrusion* (C)||1.45 in / 37 mm|
|Mounting Hole Diameter (D)||12.0625 in / 306 mm|
|Mounting Depth (E)||7.94 in / 202 mm|
|Driver Displacement||0.148 cu ft / 4.19 L|
|Net Weight||25.35 lbs / 11.5 kg|
|*Frontal grille protrusion measured from mounting surface|
|Infinite Baffle Use||Yes (preferred)|
|Min. Sealed Enclosure Volume||2.0 cu ft / 56.6 L (or larger)|
|Optimum Sealed Enclosure Volume||3.0 cu ft / 70.8 L|
Dynamic Motor Analysis – DMA Optimized Motor
JL Audio’s proprietary Dynamic Motor Analysis system is a powerful suite of FEA-based modeling systems, first developed by JL Audio in 1997 and refined over the years to scientifically address the issue of speaker motor linearity. This leads to vastly reduced distortion and faithfully reproduced transients… or put simply: tight, clean, articulate bass.
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.
Marine Materials / Testing
The design of marine products requires extensive materials testing to achieve reliability and longevity.
Building serious marine products requires a real commitment to environmental testing and materials specification. To this end, JL Audio has invested in Ultraviolet testing chambers (to simulate years of sun exposure) and Salt Fog chambers (to simulate years of exposure to salt-water environments). This testing is critical to building products that will not only sound great in your boat, but will also sound great for many, many years.
- injection-molded mica-filled polypropylene cone bodies with synthetic rubber surrounds, specifically formulated with UV inhibitors for marine duty.
- Marine-grade, synthetic fiber spiders with progressive roll designs to withstand high humidity.
- Specifically engineered polymer baskets are corrosion and UV-resistant and encapsulate the woofer’s motor system to prevent corrosion.
- Gold-plated, marine-grade brass connection terminals
- Marine-grade stainless steel mounting hardware is included.
Built in U.S.A. with Global Components
JL Audio’s Miramar, Florida loudspeaker production facility is one of the most advanced in the world.
At a time when most audio products are built overseas, JL Audio’s commitment to in-house loudspeaker production continues to grow. To pull this off in a competitive world market, our production engineering team has created one of the world’s most advanced loudspeaker assembly facilities and established a global network of quality component suppliers who build to our specifications. This, combined with our commitment to state-of-the-art assembly technology, allows our skilled workforce to efficiently build JL Audio products to extremely high quality standards, right here in the U.S.A.
Since most of our premium loudspeakers incorporate proprietary, patented technologies requiring specific assembly techniques, we find it is vital that the people who designed them have close access to the people manufacturing them. The following JL Audio products are built in our Miramar, Florida factory, with global components:
- Subwoofers: W7, W6v3, TW5v2, TW3, TW1, W3v3
- Enclosed Car Subwoofers: Stealthbox®, PowerWedge™, ProWedge™, H.O. Wedge™ & MicroSub™ Enclosed Subwoofers
- Marine Loudspeakers, Marine Subwoofers and Marine Enclosed Loudspeakers
- Home Subwoofers: Dominion™, E-Sub, Fathom® and Gotham®