4 Inch (100 mm) Commercial Loudspeaker, 5 Watt Transformer

Brand Name
Oaktron by MISCO
Model #
Part #
In stock

The OK4-T275 is a high compliance 4” driver that is resistant to corrosion and moisture. This model is attached to a 5 watt, 25 & 70 volt transformer, and 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
  • 5 watt, 25 & 70 volt line matching transformer
  • Ferrite magnet, treated cloth cone
  • Drill tapped holes (3), #8-32 

Oaktron by MISCO is a premium line of high performance, ready-to-ship transducers and drivers for a wide variety of applications including high fidelity, arcade, and casino games, automotive, aerospace and many more. From elegantly simple to highly specialized designs for unique and demanding applications, there is an Oaktron loudspeaker perfectly suited for your needs.

MISCO engineers use the world's most sophisticated loudspeaker measurement systems including the Klippel Analyzer to maximize and validate the speaker's design, as well as the Klippel QC module to ensure perfect unit to unit consistency and reliability.

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More Information
Brand Name Oaktron by MISCO
Model # OK4-T275
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) +/- 15% 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) 179.17
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 (g) 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