Dayton Audio UMII18-22
subwoofer · EBP 33 → suits a sealed box · nominal (full) — Dayton Audio UMII18-22 spec sheet (manufacturer)
Thiele/Small parameters
| Fs (resonance) | 22 Hz |
| Qts | 0.53 |
| Qes / Qms | 0.67 / 2.53 |
| Vas | 248.2 L |
| Re / nominal Z | 4.2 Ω / 4 Ω |
| Xmax | 28.0 mm |
| Sensitivity | 87.8 dB (1 W/1 m, calc); 90.7 dB (2.83 V/1 m, mfr) |
| Power handling | 1200 W |
Published (nominal) values, params full — verify by measurement (DATS/REW) before building. datasheet
Recommended enclosures
| Sealed (Qtc 0.707) — Vb | 318.4 L |
| Sealed — Fc / F3 | 29.3 / 29.4 Hz |
| Ported (suggested) — Vb | 610.9 L |
| Ported — Fb / F3 | 16.6 / 20.0 Hz |
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About this driver
The Dayton Audio UMII18-22 is a 18″ subwoofer with a free-air resonance of 22 Hz and a total Q (Qts) of 0.53. Its efficiency-bandwidth product (EBP) of 33 points toward a sealed alignment. In a 318.4 L sealed box it reaches an F3 of 29.4 Hz (Qtc 0.707); a suggested 610.9 L box tuned to 16.6 Hz extends to about 20.0 Hz. See the sealed vs ported guide for how to choose.
NOMINAL/manufacturer. Ultimax II 18in DVC; dual 2-ohm coils, params measured in series (=> 4 ohm). Fs 22 Hz; Vas 248.2 L; Sd 1184 cm2; BL 19.2 Tm; Mms 420 g; Xmax 28 mm at 70% Bl (Klippel verified); 1200 W AES; usable 20-500 Hz.
Recommended partners
modeled estimateThese tweeters could pair with the Dayton Audio UMII18-22 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.
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Crossover not modelable yet — tweeter needs published Thiele/Small data.
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Build this pair → - SB Acoustics SB29RDC-C000-4Incompatible· 0/100
Crossover not modelable yet — tweeter needs published Thiele/Small data.
Build this pair → - Seas 27TBFC/G H1212-06Incompatible· 0/100
Crossover not modelable yet — tweeter needs published Thiele/Small data.
Build this pair →
Modeled estimate from T/S + geometry — no measurements. The verdict is robust; it improves with measured FRD/ZMA data.