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SB Acoustics SB21RDCN-C000-4 Tweeter

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The SB21RDCN-C000-4 is a newly designed compact tweeter from SB Acoustics featuring a 21mm ring radiator diaphragm and neodymium magnet system. It has an excellent frequency response to above audibility. The centre of the diaphragm is inverted and bonded to an internal dimple on the pole piece, this innovation negates the need for a front phase plug.

Key Features:

  • Inverted centre phase plug free design
  • Non-resonant diaphragm design for minimum high frequency break-up
  • Copper capped pole for reduced voice coil inductance and minimum phase shift
  • Compact low distortion neodymium motor system
  • Non-resonant rear chamber with optimised damping for improved dynamics
  • CCAW voice coil for low moving mass
  • Long life silver lead wires
  • Low resonant frequency

Basic parameters:

Resonant frequency (fs) 850 Hz Nominal impedance (Zn) 4 Ω
Effective diaphragm diameter 21mm DC resistance (Re) 3.1 Ω
Ferrofluid ? Y/N Yes
Max power handling 40 W
Recommended crossover 2.6kHz/12dB Faceplate diameter 58mm
Sensitivity (2.83V/1m) 89.5dB Cutout hole diameter 40mm

Here's the full datasheet:

.pdf link