Alpine RS-W12D4 Review: A 12-Inch Shallow Sub for Tight Spaces
Updated: Oct 6
The Alpine RS-W12D4 is a 12-inch (30 cm) shallow-mount subwoofer from Alpine's R-Series with dual 4-ohm voice coils, rated at 600 W RMS (1,800 W peak) and needing only about 82 mm of mounting depth. At an Indian MRP of ₹95,999 it is the most expensive Alpine subwoofer we stock. It suits owners who want a 12-inch cone where depth is scarce, such as a slim box behind a seat or against the boot wall, and who will give it a proper sealed enclosure and a matched amplifier. Today's price is on our RS-W12D4 product page.
Key takeaways
A 12-inch cone in about 82 mm of depth, with a 4-inch voice coil and 20 mm of linear excursion.
Dual 4-ohm coils wired in parallel give 2 ohms, a direct match for a mono amplifier making 600 W at 2 ohms, such as the S2-A60M.
Alpine's guide lists sealed boxes of about 17, 25 and 34 litres net; even the largest is only about 229 mm deep outside.
We found no readable owner reviews of this 12-inch; feedback on its 10-inch sibling is positive.
Alpine RS-W12D4 specifications
Specification | Alpine RS-W12D4 |
|---|---|
Size | 12-inch (30 cm) shallow-mount subwoofer |
Voice coils | Dual 4 Ω (DC resistance 3.6 + 3.6 Ω) |
Power handling | 600 W RMS / 1,800 W peak |
Recommended power range | 500 – 600 W RMS |
Sensitivity (1 W / 1 m) | 81 dB |
Frequency response | 26 Hz – 200 Hz |
Voice coil | 4-inch (102 mm) |
Xmax | 20 mm |
Cone area | 572 cm² |
Mounting depth | 81.7 mm (Alpine USA page: 3.25 in, 82.55 mm) |
Cutout | 295 mm |
Construction | Gen2 DD Linear motor, neodymium magnet, cast aluminium frame, aluminium dust cap |
Grille | Optional KTE-RS12G steel-mesh grille kit |
India MRP | ₹95,999 |
Figures come from Alpine USA's RS-W12D4 page, which matches our listing, and Alpine's R-Series Shallow application guide for the power range, DC resistance, cone area, cutout, depth drawing and boxes. The guide lists a 25–100 Hz response and Alpine's launch release quoted 82 dB for the 12-inch, so Alpine's own documents differ on some figures.
A 12-inch cone in a slim package
Alpine's guide gives this driver 572 cm² of cone area, about half as much again as the 10-inch RS-W10's 380 cm², in a frame barely deeper than the 10-inch. The motor uses a neodymium magnet in Alpine's Gen2 DD Linear design, and the guide's cutaway lists a motor cooling fin, a vented coil former and a high-temperature 4-inch voice coil. Heat management matters for a sub that may sit in a closed boot through a Delhi summer.
On paper the larger cone doesn't clearly make it more sensitive: Alpine USA's page lists 81 dB here and Alpine UK's page 83 dB for the 10-inch RS-W10D4, but the launch release gives 82 dB for the 12-inch and 79 dB for the 10-inch, so Alpine's own figures disagree. What the 12-inch offers is a slightly deeper quoted response, 26 Hz against 29 Hz, and more cone to move air at the bottom end.
Sealed box options
Alpine's guide lists a sealed range of 0.6 to 1.5 cubic feet (about 17 to 42 litres) net and three ready-made designs, with volumes based on 19 mm MDF:
Small: about 457 x 381 x 165 mm external (18 x 15 x 6.5 in), about 17 litres (0.60 cubic feet) net.
Medium: about 559 x 406 x 178 mm (22 x 16 x 7 in), about 25 litres (0.90 cubic feet) net.
Large: about 533 x 406 x 229 mm (21 x 16 x 9 in), about 34 litres (1.20 cubic feet) net.
The small and medium boxes are thin enough for behind-seat or boot-wall installs; the large one extends lowest. Alpine's guide lists sealed designs only, and the driver itself displaces about 1.4 litres (0.05 cubic feet), already allowed for in its figures.
Wiring and amplifier matching
We sell this sub only in the dual 4-ohm version. Alpine's application diagrams show the options, and the amplifier figures below are from our listings:
One sub, coils in parallel: a 2-ohm load. The S2-A60M makes 600 W RMS at 2 ohms, exactly the sub's rating. The R2-A75M makes 750 W there, more than the rating, so its gain must be set conservatively.
One sub, coils in series: an 8-ohm load, at which most mono amplifiers make far less power. Alpine also shows each coil on its own channel as two 4-ohm loads.
Two subs: Alpine shows a 4-ohm final load. The S2-A120M (600 W at 4 ohms) or R2-A150M (700 W) would give each sub well under the 500 – 600 W range Alpine recommends, so one S2-A60M per sub is the cleaner match.
What owners and reviewers say about the Alpine RS-W12D4
We found no readable owner reviews of this exact model when we checked in October 2026. OnlineCarStereo's review page had none yet, and Crutchfield's review page exists but its content didn't load for us, so we can't report what it says. Alpine's January 2023 launch release is promotional.
The closest evidence covers the 10-inch RS-W10D4, not this 12-inch. Three OnlineCarStereo reviews of the RS-W10D4, from March 2024 to October 2025, praise its shallow design, clean output at high volume, tight and hard-hitting bass and solid build; one owner, who built their own box, advises searching for the right match. That site moderates reviews. If you own an RS-W12D4, we'd like to hear how it performs.
RS-W12D4 vs other Alpine subs
The RS-W10 costs ₹13,000 less (₹82,999), shares the 600 W RMS rating and motor design, and our listing covers both D4 and D2 versions, which makes two-sub wiring easier. The R2-W12 (₹41,999) is a conventional 12-inch rated at 750 W RMS; it needs about 163 mm of depth, roughly double, but costs less than half as much. On a tight budget, the S2-W12 (₹25,999, 600 W RMS) is the entry 12-inch.
Who should buy it, and who shouldn't
Buy the RS-W12D4 if you want a 12-inch sub but only have a thin space to give it, you are happy to build or commission one of Alpine's sealed boxes, and you will run it from a 2-ohm-capable mono amplifier around 600 W.
Look elsewhere if your boot can take a conventional box, where the R2-W12 delivers more rated power for far less, or if you want two subs on one amplifier, where the RS-W10D2 wires more conveniently. Buyers who want owner reviews first should note how little exists.
Installation notes for Indian cars
Measure carefully: a 295 mm cutout and a box at least 165 mm deep outside for the smallest design. Build from 19 mm MDF, glue and screw every joint, and fix the box solidly to the body; rough roads and speed breakers punish a loose enclosure. The optional KTE-RS12G grille is worth having if the box sits where luggage or feet can reach the cone.
Wire the amplifier with the power cable and fuse its manual specifies, give it ventilation away from direct sun, set the low-pass near 80 Hz and set the gain with a test tone. Our guide to choosing a car amplifier explains the basics. VA3 Car Studio offers professional installation and custom enclosures at our Ghaziabad studio.
Price and where to buy
The RS-W12D4 carries an MRP of ₹95,999 in our current Indian price list. We often sell below MRP, so see the current offer on the RS-W12D4 product page. Every unit we sell is a genuine Alpine product.
The bottom line
The RS-W12D4 puts a 12-inch cone, a 4-inch voice coil and 20 mm of excursion into about 82 mm of depth. It is expensive, owner feedback is thin, and a conventional sub costs far less wherever one fits. Where one doesn't, this is a practical way to get a 12-inch into the car, provided it gets one of Alpine's sealed boxes and a 2-ohm amplifier near 600 W.
Alpine RS-W12D4 FAQ
How deep is the Alpine RS-W12D4?
Alpine's drawing shows 81.7 mm of mounting depth, and its US product page quotes 3.25 inches (82.55 mm). The cutout is 295 mm, and the smallest recommended sealed box is about 165 mm deep outside.
What amplifier suits the RS-W12D4?
Wire the two 4-ohm coils in parallel for 2 ohms and use a mono amplifier making around 600 W there. The S2-A60M, rated at 600 W RMS into 2 ohms in our listing, matches the sub's rating exactly.
Can I run two RS-W12D4 subwoofers from one amplifier?
Alpine shows two dual 4-ohm subs as a 4-ohm load, where Alpine's S2-A120M and R2-A150M make only 600 and 700 W in total, well below 500 W per sub. One S2-A60M per sub is the cleaner way to run a pair.
Buy Alpine Subwoofers in India
Check the Alpine RS-W12D4 R-Series 12 Inch Shallow Subwoofer Dual 4 price in India, browse more Alpine subwoofers or compare all car subwoofers in India. Want it fitted properly? Book subwoofer installation at our Ghaziabad studio.
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