JL Audio 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 Strontiumferrite 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

C7-650cw Specifications

Speaker Type: Component Woofer

Nominal Diameter: 6.5 in. (165 mm)

Design Bandwidth: 50 Hz - 5 kHz

Nominal Impedance (Znom): 4 ohms Continuous

Power Handling: 125W

Recommended Amplifier Power: 50-175W

Net Weight: 3.28 lbs. (1.49 kg)

Driver Rear Displacement: 0.0135 cu.ft. (0.382 liters)

Min. Recommended Sealed Enclosure: 0.424 cu.ft. (12 liters)

Parameters:

Voice Coil Resistance (Re): 3.114 ohms

Free Air Resonance (Fs): 54.5 Hz

Reference Efficiency (no): 0.304%

Efficiency @ 1W/1m: 87.0 dB

SPL Sensitivity @ 2.83V/1m: 90.0 dB

SPL Electrical “Q” (Qes): 0.669

Mechanical “Q” (Qms): 6.265 T

otal 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

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