SA-15 V.2 D4

The SA-15 V.2 is a 1250W RMS, 2500W peak 15-inch subwoofer and a top-down rework of the original SA platform. Its 2.75-inch coil matches what many 3-inch coils do without the extra moving mass, and the narrower coil leaves room for a wider spider that keeps a large cone stable at full travel. Mass, motor force, and suspension stiffness are balanced for this power level.

The motor carries a large magnet shorting ring to reduce distortion and keep response even across the acoustic band, along with a vented magnetic gap and pole piece for cooling. An aluminum 2.75-inch coil former pulls heat out of the windings, and a cast aluminum vented frame spacer ring keeps air moving under the spider. High-temperature copper wire, a multi-layer spider, and doubled-up XL tinsel leads stitched to the cone handle the mechanical load.

A competition-grade paper cone, strong foam surround, and cast aluminum frame finish it. Past roughly 19mm of one-way linear excursion, the mechanical limit is 37mm one-way before the coil bottoms. Sensitivity is 87.08 dB, so the 15-inch cone converts power into output efficiently.

Dual 4-ohm coils wire to 2 ohm or 8 ohm, suited to dual-15 walls and amplifiers rated at a higher load. Target 3.0 cu ft ported with 44 sq in of port tuned to 35 Hz, or 2.0 cu ft sealed. Allow 9 inches of depth behind a 14.01-inch cutout.