4" (100 mm) Commercial Loudspeaker, 8 Watt Transformer

Brand Name
Oaktron by MISCO
Model #
OK4-T78
Part #
93129
In stock
$44.94
  • MSRP$67.99
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The OK4-T78 is a high compliance 4” driver resistant to corrosion and moisture, attached to a 8 watt, 70 volt transformer. This compact driver is ideal for low-level distribution and paging systems looking for superior sound dispersion. A rugged steel frame and a treated cloth cone create reliable sound while remaining environmentally resistance.

  • Full range speaker
  • 4" (102 mm) steel basket diameter
  • 15 watts, 8 ohms, 93 dB SPL
  • 8 watt, 70 volt line matching transformer
  • Ferrite magnet, treated cloth cone
  • 3 Drill Tapped Holes, #8-32 

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More Information
Brand Name Oaktron by MISCO
Model # OK4-T78
Size, Nominal (inch & mm) 4" (100 mm)
Shape of Speaker Round
Speaker Type Wide Range
Application Commercial, Indoor, Voice Communications
Environment Indoor
RoHS Compliant No
Nominal Impedance (Z) (Ω) 8
Rated Power IEC268-5 (W) 15 Watts
Rated Impedance (Ω) 8
Continuous Power (W) 15
Program Power (W) 30
Frequency Range (Hz) 60 - 20,000
Sensitivity (dB SPL) ¹ 93
Resonant Frequency (Fs) (Hz) 129
DC Resistance (Re) (Ω) 7.1
Voice Coil Inductance (Le) (mH) 0.2
Mechanical Q Factor (Qms) 5.52
Electrical Q Factor (Qes) 0.72
Total Q Factor (Qts) 0.64
Mechanical Resistance (Rms) (kg/s) 0.5
Compliance Equivalent Volume (Vas) (L) 2.14
Suspension Compliance (Cms) (mm/N) 0.45
Surface Area of Diaphragm (Sd) (cm²) 58.1
Moving Mass (Mms) (gm) 3.4
Motor Force Factor (BL) (T•M) 5.2
Efficiency (η₀) (%) 0.61
Efficiency Bandwidth Product (EBP) (Fs/Qes) 178.17
Basket Type Stamped steel
Terminal Size (mm) 4.8
Voice Coil Diameter (mm) 25.4
Voice Coil Wire Material Copper
Voice Coil Former Material Kraft paper
Voice Coil Winding Single Layer
Magnet Material Ferrite
Magnet Weight (gm) 283.5
Cone Body Material Treated cloth
Dust Cap Material Paper
Spider Material Cotton
Net Weight (kg) 0.99
Technical Notes

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