6.5 Inch (165 mm) Woofer with Red Carbon Fiber Cone

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This 6.5” premium woofer provides both value and performance.  A custom fabricated woven carbon fiber cone allows for a rigid piston and fast transient response.  A stylish yet sturdy round cast aluminum basket provides easy front mounting in an enclosure. The carefully designed aluminum phase plug eliminates the need for the additional mass of a dust cap and reduces lateral wave energy interference which causes unwanted peaks and dips in the frequency response. It is centered within inner and outer inductance modulating elements to reduce inductance.

  • Well vented, non-flexible cast aluminum frame
  • Rigid, low-mass woven carbon fiber cone with a decorative red thread for enhanced, distinctive appearance.
  • Bumped “T-Yoke” for extra mechanical excursion and thermal venting
  • 1.5” (38 mm) voice coil, high temperature copper wire on aluminum former
  • Aluminum phase plug for reduction of lateral wave energy interference
  • Dual inside-outside copper shorting rings for ultra-low distortion

Bold North Audio products are the most accurate, engineered audio transducers available. Each design requires Klippel vibrational test analyses to verify the key parts of optimal audio performance. While we rely heavily on objective science to lead us, we understand that most of all speakers need to tell the musical truth. Our engineers, musicians, and recording studio veterans are the final judges of when a design is worthy of the Bold North Audio brand.

All Bold North Audio products are assembled in Minnesota, with parts sourced from around the world to produce the highest combination of performance, consistency, and customer value.

More Information
Model # BWF-6503
Speaker Type Woofer
Size, Nominal (inch & mm) 6" (152 mm)
Shape of Speaker Round
Application High-End Audio and Home Theater, Home Audio, Indoor
RoHS Compliant Yes
Rated Impedance (Ω) 8
DC Resistance (Re) (Ω) 6.25
Rated Power IEC268-5 (W) 75 Watts
Program Power (W) 150
Frequency Range (Hz) 35 - 9,000
Sensitivity (dB SPL) ¹ 87
Resonant Frequency (Fs) (Hz) +/- 15% 43
Nominal Impedance (Z) (Ω) 8
Voice Coil Inductance (Le) (mH) 0.15
Mechanical Q Factor (Qms) 2.69
Electrical Q Factor (Qes) 0.43
Total Q Factor (Qts) 0.37
Moving Mass (Mms) (gm) 17.8
Suspension Compliance (Cms) (mm/N) 0.78
Mechanical Resistance (Rms) (kg/s) 1.80
Surface Area of Diaphragm (Sd) (cm²) 126.7
Compliance Equivalent Volume (Vas) (L) 17.69
Motor Force Factor (BL) (T•M) 8.37
Efficiency (η₀) (%) 0.30
Efficiency Bandwidth Product (EBP) (Fs/Qes) 100
Basket Type Cast aluminum
Terminal Size (mm) 6.4 x 0.8 / 4.7 x 0.5
Voice Coil Diameter (mm) 38
Voice Coil Wire Material Copper
Voice Coil Former Material Aluminum
Magnet Material Ferrite
Magnet Weight (g) 794
Cone Body Material Carbon fiber
Cone Surround Material Rubber
Spider Material Cotton
Dust Cap Material Aluminum
Displacement Limit Due to Force Factor Variation (mm) 5.30
Displacement Limit Due to Compliance Variation (mm) 5.63