Best Amplifier for a Car Subwoofer
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In this guide (7 sections)
Top picks at a glance
Best overallRockford Fosgate R2-500X1View on Amazon
More power at 2 ohmsSony XM-GS100View on Amazon
More powerKicker CXA800.1View on Amazon
Budget high powerSkar Audio RP-1200.1DView on Amazon
Most compactAlpine S-A60MView on Amazon
A subwoofer is only as good as the amplifier driving it. Underpower it and bass sounds weak; overpower it and you risk damage. The right monoblock (single-channel) amp matches your sub's RMS power rating at the correct impedance.
Quick answer: our top pick is the Rockford Fosgate R2-500X1 for most single-sub systems: 300W RMS at 4 ohms or 500W at 2 ohms in a small chassis. For a 2-ohm build that needs more power, the Sony XM-GS100 gives about 100W more RMS at 2 ohms.
How to match an amp to a sub
- Find your subwoofer's RMS power rating (ignore "peak" power).
- Find its final impedance (ohms) after wiring, for example a dual 4-ohm sub wired to 2 ohms.
- Choose an amp whose RMS output at that impedance is close to the sub's RMS rating.
Quick picks
| Amplifier | Type | Best for | Price |
|---|---|---|---|
| Rockford Fosgate R2-500X1 | Monoblock | Best overall | Check price |
| Sony XM-GS100 | Monoblock | More power at 2 ohms | Check price |
| Kicker CXA800.1 | Monoblock | More power for the price | Check price |
| Skar Audio RP-1200.1D | Monoblock | Budget high power | Check price |
| Alpine S-A60M | Compact monoblock | Small installs | Check price |
The best subwoofer amplifiers
Rockford Fosgate R2-500X1
Best for: Most single-sub systems, including first builds on a budget.
- Item dimensions L x W x H
- 8 x 6 x 3 inches
- Voltage
- 12 volts
- Maximum Supply Voltage
- 13 volts
- Mounting Type
- Surface Mount
- Number of Channels
- 1
- Maximum Output Power
- 500 watts
The R2-500X1 is a class-D mono amp rated at 300W RMS at 4 ohms or 500W at 2 ohms, in a small 1.9 x 6.8 x 8.5-inch chassis. Rockford's C.L.E.A.N. circuit helps you set gain correctly, and it supports a remote bass level knob.
Pros
- 300W @ 4Ω / 500W @ 2Ω RMS
- C.L.E.A.N. circuit makes gain setting easier
- Punch EQ and variable infrasonic filter
- Small, efficient class-D chassis
Cons
- Not 1-ohm stable
- Less headroom than the Kicker or Skar for big subs
Sony XM-GS100
Best for: A dual-sub or 2-ohm build that needs more RMS than the Rockford.
- Item dimensions L x W x H
- 13.38 x 10.94 x 4.38 inches
- Maximum Supply Voltage
- 14 volts
- Minimum Supply Voltage
- 14.4 volts
- Mounting Type
- Car Mount
- Number of Channels
- 1
- Maximum Output Power
- 1100 watts
The XM-GS100 is a class-D mono amp from Sony's GS Series. Sony rates it at 330W RMS at 4 ohms and 600W RMS at 2 ohms, so it gives a 2-ohm sub load about 100W more RMS than the Rockford R2-500X1.
Pros
- 600W RMS at 2 ohms
- 330W RMS at 4 ohms
- Big-brand amp at a mid-range price
Cons
- The listing shows both a 3-year and a 1-year warranty, so confirm before buying
- Larger than the Rockford, so check your mounting space
- Not rated for 1-ohm loads
Kicker CXA800.1
Best for: Larger subs that need more power.
- Power (watts/ch) 4 Ohm:
- 900x1
- Dimensions (in):
- 2-3/8 H x 6-3/4 W x 14-3/8 L
- Frequency Response (Hz):
- 25-200Hz
- Input Sensitivity:
- 125mV–5V (Low) 1V–40V (High)
- Signal-to-Noise Ratio:
- 95dB
- Active Crossover:
- Variable Lo-pass 50Hz–200Hz
The CXA800.1 is Kicker's CX-Series mono class-D amp. It is stable down to 1 ohm, so you can wire more subs, and it has a variable 12dB crossover, KickEQ bass boost up to 6dB and a 24dB subsonic filter. Mounting hardware for vertical or horizontal installs is included.
Pros
- Stable down to 1 ohm
- Variable crossover, bass boost and subsonic filter
- Vertical and horizontal mounting hardware included
- Kicker's reputation for reliability
Cons
- About 14 inches long, so it needs more space
- Check your alternator and wiring before running it hard
Skar Audio RP-1200.1D
Best for: High output builds on a tight budget.
- Item dimensions L x W x H
- 16 x 6 x 2.5 inches
- Voltage
- 14.4 volts
- Maximum Supply Voltage
- 14.5 volts
- Minimum Supply Voltage
- 8.5 volts
- Mounting Type
- Surface Mount
- Number of Channels
- 1
The RP-1200.1D is a class-D MOSFET mono amp rated at 1,200W RMS at 1 ohm (1,600W peak). It has a bass EQ switch for +6 or +12dB at 45Hz, 4-way protection and 4-gauge power and ground terminals, and comes with a remote sub level control.
Pros
- 1,200W RMS at 1 ohm for the money
- Bass boost switch at 45Hz
- 4-way protection circuitry
- Remote subwoofer level control included
Cons
- Needs 4-gauge wiring and a healthy electrical system
- 16 inches long
Alpine S-A60M
Best for: Small cars where space is tight.
The S-A60M is Alpine's compact S-Series class-D mono amp. This bundle includes the RUX-KNOB.2 remote bass control, which lets you turn the bass up or down from the driver's seat.
Pros
- Very small and easy to hide
- Includes the RUX-KNOB.2 remote bass knob
- Alpine build quality
Cons
- Lower power than the other amps here
- Best with one efficient subwoofer
Wiring kit and electrical tips
- Buy a true-gauge OFC (oxygen-free copper) wiring kit sized for your amp's current draw.
- Fuse the power wire near the battery.
- Use a short, solid ground to bare metal.
- High-power systems may need an upgraded alternator or the "Big 3" wiring upgrade.
Set amplifier gain with a test tone and a multimeter or oscilloscope if possible. A gain set too high causes clipping, which damages subwoofers faster than raw power does.
Subwoofer amp FAQ
What size amp do I need for my subwoofer?
Match the amplifier's RMS output at your sub's final impedance to the sub's RMS rating. A sub rated 500W RMS wired to 2 ohms needs an amp that makes about 500W RMS at 2 ohms. Ignore peak or max power numbers.
Is it bad to overpower a subwoofer?
A little extra headroom is fine if you set the gain correctly. The real damage comes from clipping and from turning the gain up to match a louder amp. Set the gain with test tones or a multimeter, not by ear.
Do I need a monoblock amp, or can I use a 4-channel amp?
A monoblock amp is designed to be stable at low impedance and to deliver its power to a single sub channel. Bridging two channels of a multichannel amp can work for small subs, but a monoblock is simpler and usually more efficient.
What gauge wiring kit do I need?
It depends on the amp's current draw and the length of the run. Many 500W RMS systems use a 4-gauge kit, while bigger amps need 1/0 gauge. Use oxygen-free copper rather than copper-clad aluminum, and fuse the power wire near the battery.
Bottom line
The Rockford Fosgate R2-500X1 is the best amp for most single-sub systems. For a 2-ohm load that needs more power, step up to the Sony XM-GS100, and bigger subs need the Kicker CXA800.1.
Sources
Official sources for the standards, safety rules and products in this guide. Specifications change between model years, so confirm current specs and fitment on the manufacturer's site before you buy.
- Rockford Fosgate — official site — current product specifications
- Sony — official site — current product specifications
- Kicker — official site — current product specifications
- Skar Audio — official site — current product specifications
