4-inch Drivers
FR421
The FR421 is a 4-inch ferrite full-range driver for compact speakers, soundbars and portable audio. It delivers 40 W nominal power with 87 dB sensitivity and a 91 Hz–17 kHz frequency response, using a 20 mm CCAW voice coil in a pressed-steel basket. Y35 ferrite magnet. AES standard, tested in free air.
Specifications
- Nominal Diameter
- 4" / 100 mm
- Rated Impedance
- 8 ohm
- Sensitivity (1W/1m)
- 87 dB
- Frequency Range
- 91 Hz - 17 kHz
- Voice Coil Diameter
- 20 mm / 0.8"
- Net Weight
- 0.5 kg
The FR421 is a 4-inch ferrite full-range driver designed for compact loudspeaker systems. Key specifications are listed in the table on this page. Full Thiele-Small parameters available on request – contact contact@brave-audio.com.
GENERAL SPECIFICATIONS
Nominal Diameter | 4" / 100 mm |
Rated Impedance | 8 ohm |
Nominal Power Handling | 40 W |
Program Power | 80 W |
Sensitivity (1W/1m) | 87 dB |
Frequency Range | 91 Hz - 17 kHz |
Minimum Impedance (Zmin) | 7.2 ohm |
Voice Coil Diameter | 20 mm / 0.8" |
Voice Coil Material | CCAW |
Former Material | Fibre Glass |
VC Winding Depth | 6 mm |
Number of Layers | 2 |
Magnetic Gap Depth | 4 mm |
Basket | Pressed Steel |
Flux Density | 1.2 T |
Magnet Out Diameter | 70 mm |
MOUNTING INFORMATION
Overall Diameter | 127 mm |
Bolt Circle Diameter | 115 mm |
Bolt Hole Diameter | 5 mm |
Baffle Cut-out Diameter | 103 mm |
Overall Depth | 55 mm |
Air Volume Occupied | 0.17 liters |
Net Weight | 0.5 kg |
Shipping Weight | 14 kg / 24 pcs |
Shipping Carton Size | 430 x 340 x 225 mm |
THIELE-SMALL PARAMETERS
Fs (Resonance Frequency) | 92 Hz |
Re (DC Resistance) | 6.4 ohm |
Qms (Mechanical Factor) | 4 |
Qes (Electrical Factor) | 1.1 |
Qts (Total Factor) | 0.88 |
Cms (Compliance) | 0.65 mm/N |
Rms (Mechanical Resistance) | 0.66 kg/s |
Mms (Moving Mass) | 4.5 g |
BL Factor | 3.9 T.m |
Vas (Equivalent Air Load) | 2.5 liters |
Sd (Piston Area) | 53 cm2 |
Xmax (Linear Excursion) | +/- 2 mm |
Xdam (Excursion before Damage) | +/- 5.5 mm |
Le (Voice Coil Inductance) | 0.3 mH |
EBP (Efficiency Bandwidth Product) | 83 |
Half-space Efficiency | 0.18 % |
