JL Audio C7-650cw 6.5″ Component Woofer – Single Woofer

C7 is the pinnacle of JL Audio automotive loudspeaker design, benefiting from our most advanced development tools and a complete commitment to precision manufacturing.

The C7-650cw component woofer is capable of operating in a 3-way system, with a midrange and tweeter, or with only a tweeter in a 2-way configuration. Engineered from the ground up, it has exceptional linear excursion capability and outstanding linearity, resulting in solid mid-bass and pure, precise, mid-range performance. Distortion and non-linearities have been minimized through critical optimization of dynamic motor and suspension behaviors.

Passive crossover networks are not included with C7 drivers, as they are designed for active systems. Instead, we recommend a high-quality tuning DSP, such as the JL Audio TwK™ 88 or D8, and a dedicated amplifier channel for each C7 loudspeaker in the system. Precise setup of equalization, delay and crossover filters will ensure optimal in-vehicle performance.

C7-650cw Design Notes

Cone and Dust Cap
Vacuum-formed, mineral-filled polypropylene material offers excellent damping and low mass. The cone body features a gentle curvilinear profile to optimize response. A specially shaped dust cap attaches to the cone body and the voice coil former to improve high frequency behavior.

Suspension Design
The moving assembly is suspended and damped via a large-diameter, linear profile spider formed from a Nomex®/polycotton blend, and a positive-roll, rubber surround. The two combine to provide optimum damping without prematurely restricting the C7-650cw’s outstanding excursion capability.

Motor Design
The C7-650cw employs a high-density magnetic circuit with a high-grade Y35 Strontium-ferrite magnet, and a specially machined, T-Yoke motor topology. Motor magnetics have been precisely optimized utilizing advanced FEA tools to reduce distortion and provide linear motor force throughout the driver’s performance range.

A 32 mm (1.27 inch) diameter, overhung voice coil is employed, wound with copper wire onto a fiberglass voice coil former. The oversized voice coil offers extended power handling capability, minimizing thermal compression and distortion at higher listening levels. Chassis Design: A purpose-engineered cast alloy basket is employed, featuring thin spokes to maximize rear open area, and our Patented Elevated Frame Cooling technology.

Design Bandwidth
With 48 dB/octave filters: 50 Hz – 5 kHz
With 24 dB/octave filters: 60 Hz – 5 kHz
With 12 dB/octave filters: 70 Hz – 5 kHz

Built in USA with Global Components
Sold individually, with a cast-alloy grille tray, one fine mesh steel grille insert and one spiral steel grille insert.

The performance of every C7 driver is tested and verified, then assigned a unique serial number. Register your C7 loudspeaker online to receive a copy of its specific Acoustical Test Report.

Specifications

General Specifications

Continuous Power Handling (RMS) 125 W
Peak Music Power 225 W
Recommended Amplifier Power (RMS) 50 – 175 W / Ch.
Nominal Impedance 4 Ω
Frequency Response 50 Hz – 5 KHz ± 3 dB

Parameters

Voice Coil Resistance (Re) 3.114 Ω
Free Air Resonance (Fs) 54.5 Hz
Reference Efficiency (no) 0.304%
Efficiency 87.0 dB @ 1W / 1m
93.0 dB @ 1W / 0.5m
Sensitivity 90.0 dB @ 2.83V / 1m
Electrical “Q” (Qes) 0.669
Mechanical “Q” (Qms) 6.265
Total Speaker “Q” (Qts) 0.605
Equivalent Compliance (Vas) 0.461 cu. ft. (13.05 liters)
Moving Mass (Mms) 17.679 g
Mechanical Compliance (Cms) 0.000482 m/N
Magnetic Strength (BL) 5.31 N/A
Effective Piston Area (Sd) 21.4 sq. in. (0.013807 sq. m)
One Way Linear Excursion (Xmax) 5 mm

Woofer Physical Specifications

Frame Outer Diameter (A) 6.50 in / 165 mm
Bolt Hole Circle Diameter (B) 6.12 in / 155 mm
Mounting Hole Diameter (C) 5.56 in / 141 mm
Grille Tray Outer Diameter (D) 7.20 in / 183 mm
Frontal Grille Protrusion* (E) 0.98 in / 25 mm
Mounting Depth (F) 2.77 in / 70 mm
Motor Outer Diameter (G) 3.94 in / 100 mm

*Frontal grille protrusion measured from mounting surface

Technology

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.

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.

Elevated Frame Cooling (U.S. Patent #6,219,431 & #6,229,902)

JL Audio’s patented Elevated Frame Cooling design delivers cool air through slots directly above the top-plate to the voice coil of the speaker. This not only enhances power handling, but also sound quality by minimizing dynamic parameter shifts and power compression.

Detailed Information:
Many speakers employ venting techniques to enhance voice coil cooling. This is typically accomplished by having big holes in the sides of the frame just below the spider attachment shelf. While it provides a modest cooling benefit, this low-velocity air-flow does not blow directly or strongly on the voice coil.

Our patented design improves upon this cooling technique in a number of ways. By elevating the frame above the top-plate of the motor (via stand-offs integrated into the bottom of the frame) a narrow, high-velocity air-path is created between the bottom surface of the frame and the top surface of the top-plate. This air path leads directly to the voice coil and then turns upward into the spider air cavity. By utilizing the pumping action of the spider through this focused air path, a large volume of cool air hits the coil windings directly.

Another important benefit is that the upper surface of the top-plate (one of the speaker’s hottest parts) is directly exposed to cooling air flow, whereas on a conventional design it is isolated from the air flow by the lower flange of the frame. The elevated frame technology greatly increases thermal power handling, reduces compression effects and does so without any additional parts.