Alpine R2-A150M Review: 1,500 W at 1 Ohm for a Two-Sub System
Updated: Oct 6
The Alpine R2-A150M is a Class D mono subwoofer amplifier from Alpine's second-generation R-Series, rated at 700 W RMS into 4 Ω, 1,200 W into 2 Ω and 1,500 W into 1 Ω, all at 14.4 V. With an Indian MRP of ₹61,999, it's the most powerful of the three R-Series amplifiers we sell, priced above the 750 W R2-A75M. It's aimed at two-subwoofer systems, and it suits owners who are ready to upgrade their car's wiring to match. Today's price is on our Alpine R2-A150M product page.
Quick summary
Rated at 700 W RMS into 4 Ω, 1,200 W into 2 Ω and 1,500 W into 1 Ω at 14.4 V, with THD+N of 1.0% or less at each.
Two Alpine R2-W12D4 or R2-W10D4 subwoofers wired to 1 Ω get 750 W each, matching their RMS rating.
It needs a main fuse of 150 A or more, and Alpine limits 4 AWG power cable to 4 m for a single amp, so many installs will need heavier wiring.
At a 2 Ω load, the cheaper S2-A120M carries the same 1,200 W rating, so the R2-A150M's extra rated power appears at 4 Ω and 1 Ω.
Alpine R2-A150M specifications
Specification | R2-A150M |
|---|---|
Type | Class D mono subwoofer amplifier |
Power into 4 Ω (14.4 V) | 700 W RMS × 1 |
Power into 2 Ω (14.4 V) | 1,200 W RMS × 1 |
Power into 1 Ω (14.4 V) | 1,500 W RMS × 1 |
THD+N at rated power | 1.0% or less (4, 2 and 1 Ω) |
Frequency response | 10–400 Hz (+0/−3 dB) |
Low-pass and subsonic filters | 50–400 Hz and 8–40 Hz, both −24 dB/oct. |
Bass EQ | 0 to +12 dB at 50 Hz |
Signal-to-noise ratio | Over 75 dB at 1 W; over 103 dB at rated power |
Fuses | 25 A × 6 internal; main fuse of 150 A or more |
Power cable (single amp) | 4 AWG (21 mm²), up to 4 m |
Dimensions and weight | 341 × 65 × 185 mm; 5.0 kg |
India MRP | ₹61,999 |
Figures come from Alpine's R2-A150M owner's manual; Alpine India's product page lists the same three power ratings.
Power at 4 Ω, 2 Ω and 1 Ω
Into 4 Ω the R2-A150M makes 700 W, into 2 Ω 1,200 W, and into 1 Ω 1,500 W, each at 1.0% THD+N or less. That last step is what sets it apart: Alpine's S-Series monos are also rated at 1 Ω, but their 1 Ω figures equal their 2 Ω figures, whereas this amp gains 300 W. Alpine's manual says the total load of a two-subwoofer or dual-voice-coil system must not drop below 1 Ω.
That makes two Alpine 750 W subwoofers the natural partner. Take two Alpine R2-W12 or R2-W10 subs in their dual 4 Ω (D4) versions, wire each sub's coils in parallel for 2 Ω, then wire the two subs in parallel: the amp sees 1 Ω and delivers 1,500 W, or 750 W per sub, exactly their RMS rating. Two dual 2 Ω (D2) versions, each wired in series and then paralleled, present 2 Ω and get 1,200 W, or 600 W each.
With a single 750 W sub, the closest match is 4 Ω, using a D2 version wired in series for 700 W; at 2 Ω or 1 Ω that sub would be offered more than its rating. For one sub, the R2-A75M delivers 750 W into 2 Ω and costs less.
The wiring an amp this size needs
No other R- or S-Series amp we sell calls for a bigger main fuse: Alpine specifies 150 A or more, and the amp carries six 25 A fuses of its own. For a single amp, the manual lists 4 AWG (21 mm²) cable only for runs of up to 4 m. In a sedan or SUV, the run from the battery to the boot can easily exceed that, so plan for heavier cable; we size it to the car.
Every rating also assumes 14.4 V. With the AC running in stop-start traffic, a car's charging system may hold less than that, and the amp may deliver less than its ratings. Before fitting an amplifier of this size, have the battery and alternator checked, and consider upgrading the main earth and alternator cables; ask us what your car can support.
Tuning tools match the R2-A75M: a 50–400 Hz low-pass and an 8–40 Hz subsonic filter, both at 24 dB per octave, bass EQ of up to 12 dB at 50 Hz, and support for Alpine's RUX-KNOB.2 remote level control. The inputs accept pre-outs or, on the HI setting, factory speaker-level signals through Alpine's Speaker-RCA conversion cable, with a DC-offset auto turn-on, which helps when keeping a factory touchscreen.
What owners and reviewers say about the Alpine R2-A150M
Feedback is limited to retailer reviews. Here's what we found when we checked in October 2026.
On OnlineCarStereo, four reviews dated March to June 2024 are all positive. Buyers mention the looks and sound quality, strong output, and an amp that works as advertised; one, comparing it with earlier sub amps, judged its power ample, perhaps enough for four subwoofers, and singled out the responsive bass boost and low-pass controls, while another had no complaints, called it a very high quality amp and said it was worth the spend. OnlineCarStereo moderates reviews to remove unproven negative comments, so treat this as a small, favourable sample.
We found no magazine test or independent bench result for this model, and Alpine's own pages are promotional. If you run one in India, we'd welcome a note on how it behaves on a hot day with the AC on.
R2-A150M vs S2-A120M and R2-A75M
The closest rival is Alpine's own S2-A120M, at ₹55,999 MRP. Into 2 Ω both are rated at 1,200 W RMS. The S2-A120M is rated at 600 W into 4 Ω and stays at 1,200 W into 1 Ω, where the R2-A150M offers 700 W and 1,500 W. On paper the S2-A120M also quotes a higher signal-to-noise ratio (over 85 dB at 1 W against over 75 dB), and its manual calls for a main fuse of 100 A or more rather than 150 A.
On rated power the decision is simple. If your subs will be wired to 2 Ω, the S2-A120M gives you the same rated power for ₹6,000 less MRP. The R2-A150M is rated higher at 1 Ω, which suits two D4 subs, and at 4 Ω, where it adds 100 W. Against the R2-A75M (₹55,999 MRP, 750 W into 2 Ω), it's the model with a 1 Ω rating and more power at 4 Ω and 2 Ω.
Who should buy it, and who shouldn't
Buy the R2-A150M if you're building a two-subwoofer system around R2-W10D4 or R2-W12D4 drivers at 1 Ω, want an R-Series amp to sit alongside an R2-A60F four-channel, and are prepared to upgrade the car's power wiring.
Look elsewhere if you're running one 750 W subwoofer, where the R2-A75M matches its rating at 2 Ω; if your system will settle at 2 Ω, where the S2-A120M matches its rated power for less; or if your car's electrical system can't be upgraded. Our guide to figuring out the need for an amplifier covers the basics of sizing one.
Installation notes for Indian cars
Alpine's manual says the amplifier must be mounted where air can circulate freely, such as the boot, because of the heat it produces. At 341 × 185 mm it needs a proper mounting board; leave space around it, keep it out of direct sun through the rear glass, and don't let luggage pile against the heat sink. Two subwoofers and this amp will take a fair share of a hatchback's boot, so ask us to check the space in your car.
Set the gain with a test tone and, in a ported enclosure, set the subsonic filter just below the port tuning. Treat the bass EQ as a last resort, since each 3 dB of boost doubles the power demand. VA3 Car Studio in Ghaziabad offers professional installation, including power wiring sized for the run in your car.
Price and where to buy
The Alpine R2-A150M carries an MRP of ₹61,999 in the Indian price list effective 1 June 2026. VA3 Car Studio often sells below MRP, so check today's offer on the R2-A150M product page. Every unit we sell is a genuine Alpine product.
The bottom line
The R2-A150M is a serious two-sub amplifier: 1,500 W into 1 Ω, a full set of bass filters and factory-head-unit inputs in a 5 kg chassis. Its value depends on the load. At 1 Ω with two R2 subs it delivers exactly what they're rated for; at 2 Ω the cheaper S2-A120M carries the same rating. Budget for proper wiring, and buy it for the specification rather than a crowd of reviews.
Alpine R2-A150M FAQ
How many subwoofers should the Alpine R2-A150M power?
Two is the natural load. Two R2-W12D4 or R2-W10D4 subs, each with its coils in parallel and the pair wired in parallel, present 1 Ω, where the amp is rated at 1,500 W RMS, or 750 W per sub, matching each sub's rating.
What fuse and power cable does the R2-A150M need?
Alpine specifies a main fuse of 150 A or more and, for a single amplifier, 4 AWG (21 mm²) cable for runs of up to 4 m. Many battery-to-boot runs are longer than that, so ask us to size heavier cable for your car.
Is the R2-A150M worth it over the S2-A120M?
On rated power, only if you will use 1 Ω or 4 Ω. Into 2 Ω both are rated at 1,200 W RMS and the S2-A120M has a ₹6,000 lower MRP; into 1 Ω the R2-A150M is rated at 1,500 W against 1,200 W, and into 4 Ω at 700 W against 600 W.
Buy the Alpine R2-A150M R-Series Mono Amplifier 1500W in India
You can buy the Alpine R2-A150M R-Series Mono Amplifier 1500W online from VA3 Car Studio with pan-India shipping. See more Alpine amplifiers, compare other mono amplifiers, or book amplifier installation in Ghaziabad.
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