Memphis Audio brought its MOJO name back to SEMA 2026 with a new top-end pairing: the MJ1812LVS, an 18-inch subwoofer rated at 4,000 W RMS, and the MJP4000LVS, a mono amplifier built to drive it. It’s a competition-grade combination aimed at people chasing serious SPL, and it was announced at the show in early November.
The short version
- MJ1812LVS: 18-inch sub, 4,000 W RMS / 8,000 W peak, 3.5-inch aluminum voice coil, 330 oz magnet.
- Impedance is selectable between 1 Ω and 2 Ω with a “FLEX” jumper; the sub is reconeable.
- MJP4000LVS: mono amp rated 1,500 W at 4 Ω, 2,500 W at 2 Ω and 4,000 W at 1 Ω, with a bass knob included.
- No prices or ship dates yet.
- A system like this needs major electrical upgrades before anything else.
The specs
| MJ1812LVS subwoofer | MJP4000LVS amplifier | |
|---|---|---|
| Power (Memphis) | 4,000 W RMS, 8,000 W peak | 1,500 W at 4 Ω, 2,500 W at 2 Ω, 4,000 W at 1 Ω |
| Key hardware | 3.5-inch aluminum voice coil, 330 oz magnet, front and back-plate venting, carbon-fiber dust cap | Extruded aluminum chassis, 12 dB/octave crossovers |
| Impedance / setup | 1 Ω or 2 Ω via FLEX jumper | Variable crossover and bass boost, strappable |
| Extras | Reconeable | Bass knob included |
The two are designed as a pair: wire the sub at 1 Ω and the amp’s 1 Ω rating matches the sub’s 4,000 W RMS exactly. Our amp matcher shows the same logic for more ordinary subs.
What it takes to run one
- Current: an amp making 4,000 W at roughly 80% efficiency draws about 360 A from a 13.8 V system at full output. That’s beyond a single 1/0 run; our wire and fuse calculator shows the options.
- Charging system: the Big 3 upgrade is the minimum, and a high-output alternator plus extra AGM batteries are normal at this level.
- Box: an 18-inch sub at this power needs a large, heavily braced enclosure, usually ported for SPL.
- Gain setting: setting the gain carefully matters even more here; see our multimeter guide.
Should you wait?
If you’re building a competition or demo vehicle and like Memphis, it makes sense to wait for prices and full Thiele/Small parameters. For a daily driver, a pair of 12s on 1,000–1,500 W gives most people more bass than they’ll use; our competition subwoofer guide covers the high-power options already on sale.
Our take
A matched 18-inch sub and 1 Ω amp is a tidy way to sell a big SPL system, and the selectable impedance adds flexibility. The numbers are only half the story, though: without published parameters, box recommendations and prices, it’s too early to say how it compares with established 18s. We’ll update this post when Memphis lists them.