SB Acoustics SB12MNRX2-25-4
midrange · EBP 181 → suits a ported box · nominal (full) — SB Acoustics datasheet (https://sbacoustics.com/wp-content/uploads/2021/03/4in-SB12MNRX2-25-4.pdf)
Thiele/Small parameters
| Fs (resonance) | 63.5 Hz |
| Qts | 0.32 |
| Qes / Qms | 0.35 / 4.19 |
| Vas | 5.3 L |
| Re / nominal Z | 3.2 Ω / 4 Ω |
| Xmax | — |
| Sensitivity | 87.7 dB (1 W/1 m, calc); 90.5 dB (2.83 V/1 m, mfr) |
| Power handling | 50 W |
Published (nominal) values, params full — verify by measurement (DATS/REW) before building.
Datasheet (PDF) ↗ — manufacturer-hosted
Recommended enclosures
This is a midrange; Thiele/Small box parameters are not used for enclosure design.
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About this driver
The SB Acoustics SB12MNRX2-25-4 is a 4″ midrange with a free-air resonance of 63.5 Hz and a total Q (Qts) of 0.32. Its efficiency-bandwidth product (EBP) of 181 points toward a ported alignment. See the sealed vs ported guide for how to choose.
Recommended partners
modeled estimateThe tweeters below pair well with the SB Acoustics SB12MNRX2-25-4 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.
- Seas 27TBFC/G H1212-06Good match· 92/100
Suggested crossover 2.06 kHz (4th-order, Linkwitz-Riley)
Build this pair → - SB Acoustics SB29RDC-C000-4Good match· 92/100
Suggested crossover 2.06 kHz (4th-order, Linkwitz-Riley)
Build this pair → - Dayton Audio EC30-4Good match· 92/100
Suggested crossover 2.06 kHz (4th-order, Linkwitz-Riley)
Build this pair → - SB Acoustics SATORI TW29BGood match· 92/100
Suggested crossover 2.06 kHz (4th-order, Linkwitz-Riley)
Build this pair → - SB Acoustics SATORI TW29B-BGood match· 92/100
Suggested crossover 2.06 kHz (4th-order, Linkwitz-Riley)
Build this pair → - SB Acoustics SATORI TW29BNGood match· 92/100
Suggested crossover 2.06 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.