Dayton Audio RS125P-4
woofer · EBP 123 → suits a ported box · nominal (full) — Dayton Audio datasheet (https://www.daytonaudio.com/images/resources/295-371--rs125p-4-spec-sheet.pdf)
Thiele/Small parameters
| Fs (resonance) | 70 Hz |
| Qts | 0.48 |
| Qes / Qms | 0.57 / 3.19 |
| Vas | 4.0 L |
| Re / nominal Z | 3.1 Ω / 4 Ω |
| Xmax | 4.0 mm |
| Sensitivity | 85.6 dB (1 W/1 m, calc); 90 dB (2.83 V/1 m, mfr) |
| Power handling | 30 W |
Published (nominal) values, params full — verify by measurement (DATS/REW) before building.
Datasheet (PDF) ↗ — manufacturer-hosted
Recommended enclosures
| Sealed (Qtc 0.707) — Vb | 3.4 L |
| Sealed — Fc / F3 | 103.1 / 103.1 Hz |
| Ported (suggested) — Vb | 7.1 L |
| Ported — Fb / F3 | 58.6 / 53.2 Hz |
Affiliate disclosure: some links are affiliate links and we may earn a commission on qualifying purchases at no extra cost to you. Prices are estimates at the time of writing; verify on the retailer's site.
About this driver
The Dayton Audio RS125P-4 is a 4″ woofer with a free-air resonance of 70 Hz and a total Q (Qts) of 0.48. Its efficiency-bandwidth product (EBP) of 123 points toward a ported alignment. In a 3.4 L sealed box it reaches an F3 of 103.1 Hz (Qtc 0.707); a suggested 7.1 L box tuned to 58.6 Hz extends to about 53.2 Hz. See the sealed vs ported guide for how to choose.
Recommended partners
modeled estimateThe tweeters below pair well with the Dayton Audio RS125P-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 1.98 kHz (4th-order, Linkwitz-Riley)
Build this pair → - SB Acoustics SB29RDC-C000-4Good match· 92/100
Suggested crossover 1.98 kHz (4th-order, Linkwitz-Riley)
Build this pair → - Dayton Audio EC30-4Good match· 92/100
Suggested crossover 1.98 kHz (4th-order, Linkwitz-Riley)
Build this pair → - SB Acoustics SATORI TW29BGood match· 92/100
Suggested crossover 1.98 kHz (4th-order, Linkwitz-Riley)
Build this pair → - SB Acoustics SATORI TW29B-BGood match· 92/100
Suggested crossover 1.98 kHz (4th-order, Linkwitz-Riley)
Build this pair → - SB Acoustics SATORI TW29BNGood match· 92/100
Suggested crossover 1.98 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.