The SB Acoustics SB12NRX25-4 is a 4 inch 4 ohm midwoofer featuring a Norex cone. Norex is a proprietary paper based material comprised of wood pulp and selected natural fibres blended for an optimally strong but lightweight cone that gives detailed sound with good midrange extension.
Also available in 8 ohms: SB12NRX25-8.
Proprietary cone material with natural fibres made in-house.
High damping Butyl rubber surround for non-resonant sound character.
Vented cast aluminium chassis for optimum strength and low compression.
Vented pole piece for reduced compression.
CCAW voice coil for reduced moving mass.
Non-conducting fibre glass coil former for minimum damping.
Long life silver lead wires.
Faraday shorting ring in motor system for reduced distortion.
Resonant frequency (fs)
Nominal impedance (Zn)
Mechanical Q factor (Qms)
DC resistance (Re)
Electrical Q factor (Qes)
Max power handling
Total Q factor (Qts)
Equivalent volume (Vas)
Here's the full datasheet:
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