4″ SB12NRX25-4 / Norex

Features

  • Proprietary cone material with natural fibres made in-house
  • High damping Butyl rubber surround for non-resonant sound character
  • Vented pole piece for reduced compression
  • Vented cast aluminium chassis for optimum strength and low compression
  • CCAW voice coil for reduced moving mass
  • Long life silver lead wires
  • Non-conducting fibre glass coil former for minimum damping
  • Shorting ring in motor system for reduced distortion

Specs

  • Nominal Impedance 4 Ω
  • DC resistance, Re 3.1 Ω
  • Voice coil inductance, Le 0.14 mH
  • Effective piston area, Sd 50 cm2
  • Voice coil diameter 25.4 mm
  • Voice coil height 15 mm
  • Air gap height 5 mm
  • Linear coil travel (p-p) 10 mm
  • Magnetic flux density 0.84 T
  • Magnet weight 0.32 kg
  • Net weight 0.76 kg
  • Free air resonance, Fs 55 Hz
  • Sensitivity (2.83 V / 1 m) 87.5 dB
  • Mechanical Q-factor, Qms 3.2
  • Electrical Q-factor, Qes 0.46
  • Total Q-factor, Qts 0.40
  • Moving mass incl. air, Mms 5.6 g
  • Force factor, Bl 3.6 Tm
  • Equivalent volume, VAS 5.6 liters
  • Compliance, Cms 1.57 mm/N
  • Mechanical loss, Rms 0.6 kg/s
  • Rated power handling* 30 W

* IEC 268-5, T/S parameters measured on drive units that are broken in.