Sine Design

Dayton Audio UM18-22

subwoofer · EBP 31 → suits a sealed box · nominal (full) — Dayton Audio spec sheet (manufacturer)

Thiele/Small parameters

Fs (resonance)26.2 Hz
Qts0.7
Qes / Qms0.85 / 4.05
Vas144.7 L
Re / nominal Z4.3 Ω / 4 Ω
Xmax22.0 mm
Sensitivity86.7 dB (1 W/1 m, calc); 89.5 dB (2.83 V/1 m, mfr)
Power handling1000 W

Published (nominal) values, params full — verify by measurement (DATS/REW) before building. datasheet

Recommended enclosures

Sealed (Qtc 0.707) — Vb7199.0 L
Sealed — Fc / F326.5 / 26.5 Hz
Ported (suggested) — Vb891.9 L
Ported — Fb / F314.9 / 20.0 Hz

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About this driver

The Dayton Audio UM18-22 is a 18″ subwoofer with a free-air resonance of 26.2 Hz and a total Q (Qts) of 0.7. Its efficiency-bandwidth product (EBP) of 31 points toward a sealed alignment. In a 7199.0 L sealed box it reaches an F3 of 26.5 Hz (Qtc 0.707); a suggested 891.9 L box tuned to 14.9 Hz extends to about 20.0 Hz. See the sealed vs ported guide for how to choose.

Ultimax; dual 2 ohm VC, params with coils in series; Vd 2681 cm3.

Recommended partners

modeled estimate

These tweeters could pair with the Dayton Audio UM18-22 in a two-way design, but the seed Thiele/Small data is too thin to grade the match yet — add or measure T/S (Fs, Sd, Xmax) to compute a real compatibility grade. You can still open a pair in the guided builder.

Modeled estimate from T/S + geometry — no measurements. The verdict is robust; it improves with measured FRD/ZMA data.

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