Detroit 820 - 8 Inch Guitar Speaker, 20 Watt, 4 Ohm

Brand Name
Part #
In stock


Turn heads with this 8-inch hemp guitar speaker, the Detroit 820. This model brings out an organic and vintage tweed sound, creating warm and full lows, strong barky mids, and creamy highs to round out the top end.

The Detroit 820 is the perfect choice for guitarists looking for an upgrade to their blues or rock tone. High sensitivity, a hemp composite cone, a powerful ferrite magnet, dual-lug terminals for easy connectivity, and a sturdy steel basket come together to enhance your style and sound to make you the talk of the town.

  • American tone guitar speaker
  • 8 inch (203 mm) steel basket diameter
  • 20 watts, 4 ohm, 94 dB SPL
  • 1-inch copper voice coil, Kraft paper former
  • 10 oz ferrite magnet
  • USA-made hemp cone

CHECK OUR DISTRIBUTORS PAGE for international customers to see what is near you.

ToneSpeak guitar speakers result from years and years of deep-dive for the perfect tone. Decades of testing, field experience, and conversations with elite tone-chasers have all been poured into these fine products. When you play ToneSpeak, you play the best.

More Information
Brand Name ToneSpeak
Size, Nominal (inch & mm) 8" (203 mm)
Shape of Speaker Round
Speaker Type Guitar Speaker
Application Musical Instruments
Environment Indoor
RoHS Compliant Yes
Nominal Impedance (Z) (Ω) 4
Rated Power IEC268-5 (W) 20 Watts
Rated Impedance (Ω) 4
Continuous Power (W) 20
Program Power (W) 40
Frequency Range (Hz) 80 - 10,000
Sensitivity (dB SPL) ¹ 94
Resonant Frequency (Fs) (Hz) +/- 15% 139
DC Resistance (Re) (Ω) 3.4
Voice Coil Inductance (Le) (mH) 0.12
Mechanical Q Factor (Qms) 15.36
Electrical Q Factor (Qes) 4.45
Total Q Factor (Qts) 3.45
Mechanical Resistance (Rms) (kg/s) 0.47
Compliance Equivalent Volume (Vas) (L) 10.92
Suspension Compliance (Cms) (mm/N) 0.16
Surface Area of Diaphragm (Sd) (cm²) 221.67
Moving Mass (Mms) (gm) 8.28
Magnetic Gap Height (mm) 6.0
Coil Winding Height (mm) 6.35
Motor Force Factor (BL) (T•M) 2.36
Efficiency (η₀) (%) 0.64
Efficiency Bandwidth Product (EBP) (Fs/Qes) 31.46
Basket Type Stamped steel with black powder coat
Terminal Size (mm) 5.2 x 0.5
Voice Coil Wire Material Copper
Voice Coil Former Material Nomex
Voice Coil Winding Style Single Layer
Magnet Material Ferrite
Magnet Weight (g) 283.5
Cone Body Material Hemp
Dust Cap Material Felt
Spider Material Cotton
Net Weight (kg) 1.01
Technical Notes

¹ Sensitivity is measured with 2.83 volt input, measured on-axis at 1 meter distance