SB Acoustics SB21RDCN-C000-4
tweeter · EBP 347 → suits a ported box · nominal (partial) — SB Acoustics datasheet (https://sbacoustics.com/wp-content/uploads/2020/04/SB21RDCN-C000-4.pdf)
Thiele/Small parameters
| Fs (resonance) | 850 Hz |
| Qts | 1.28 |
| Qes / Qms | 2.45 / 2.71 |
| Vas | — |
| Re / nominal Z | — / — |
| Xmax | — |
| Sensitivity | 89.5 dB (2.83 V/1 m, mfr) |
| Power handling | 40 W |
Published (nominal) values, params partial — verify by measurement (DATS/REW) before building.
Datasheet (PDF) ↗ — manufacturer-hosted
Recommended enclosures
This is a tweeter; Thiele/Small box parameters are not used for enclosure design.
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About this driver
The SB Acoustics SB21RDCN-C000-4 is a tweeter with a free-air resonance of 850 Hz and a total Q (Qts) of 1.28. Its efficiency-bandwidth product (EBP) of 347 points toward a ported alignment. See the sealed vs ported guide for how to choose.
Recommended partners
modeled estimateThe woofers and midranges below pair well with the SB Acoustics SB21RDCN-C000-4 in a two-way design — each grade is a modeled estimate of the crossover match, with a suggested crossover point. Open any pair in the guided builder to design the crossover and total the parts.
- Peerless by Tymphany TC9FD18-08Good match· 96/100
Suggested crossover 2.42 kHz (4th-order, Linkwitz-Riley)
Build this pair → - Dayton Audio CE65W-8Good match· 92/100
Suggested crossover 3.26 kHz (4th-order, Linkwitz-Riley)
Build this pair → - Dayton Audio DS90-8Good match· 92/100
Suggested crossover 2.61 kHz (4th-order, Linkwitz-Riley)
Build this pair → - Dayton Audio ND65-4Good match· 92/100
Suggested crossover 3.70 kHz (4th-order, Linkwitz-Riley)
Build this pair → - Dayton Audio ND65-8Good match· 92/100
Suggested crossover 3.59 kHz (4th-order, Linkwitz-Riley)
Build this pair → - Dayton Audio ND90-4Good match· 92/100
Suggested crossover 2.61 kHz (4th-order, Linkwitz-Riley)
Build this pair →
Modeled estimate from T/S + geometry — no measurements. The verdict is robust; it improves with measured FRD/ZMA data.