Sine Design

Eminence ALPHA-12A

woofer · EBP 56 → suits either box · nominal (full) — Eminence datasheet (https://cdn.shopify.com/s/files/1/0270/8665/1462/files/Alpha_12A.pdf)

Thiele/Small parameters

Fs (resonance)49 Hz
Qts0.77
Qes / Qms0.88 / 6.53
Vas121.5 L
Re / nominal Z6.3 Ω / 8 Ω
Xmax2.4 mm
Sensitivity93.9 dB (1 W/1 m, calc); 95.6 dB (2.83 V/1 m, mfr)
Power handling150 W

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

Datasheet (PDF) ↗ — manufacturer-hosted

Recommended enclosures

Sealed (Qtc 0.707) — VbInfinity L
Sealed — Fc / F349.0 / 45.3 Hz
Ported (suggested) — Vb1025.5 L
Ported — Fb / F325.3 / 22.3 Hz
Open in designer →Use my measured parameters →Buy at Parts Express →

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About this driver

The Eminence ALPHA-12A is a 12.5″ woofer with a free-air resonance of 49 Hz and a total Q (Qts) of 0.77. Its efficiency-bandwidth product (EBP) of 56 points toward either alignment. In a Infinity L sealed box it reaches an F3 of 45.3 Hz (Qtc 0.707); a suggested 1025.5 L box tuned to 25.3 Hz extends to about 22.3 Hz. See the sealed vs ported guide for how to choose.

Recommended partners

modeled estimate

The tweeters below pair well with the Eminence ALPHA-12A 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.

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

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