Sky High Car Audio FXB Subwoofer Series

Shop Sky High Car Audio FXB Series subwoofers in 6.5-inch, 8-inch, 10-inch, 12-inch, 15-inch and 18-inch sizes. The FXB Series is designed for customers stepping beyond a basic bass upgrade and building louder daily-driver systems with stronger amplifier power, properly designed enclosures and dependable electrical support.

With compact options for limited-space installations and larger models for serious trunk, hatchback and SUV builds, the FXB lineup gives customers several ways to build around the available vehicle space and desired output.

FXB subwoofers are available with dual 2-ohm and dual 4-ohm voice coils. Select the voice-coil configuration according to the number of subwoofers, amplifier capabilities and final impedance planned for the completed system.

Shop Sky High FXB Series Subwoofers

Sky High FXB 6.5-Inch Subwoofer

The Sky High Car Audio FXB Series 6.5-inch subwoofer is rated for 400 watts RMS and is available with dual 2-ohm or dual 4-ohm voice coils.

The compact 6.5-inch FXB can be a strong choice for:

  • Behind-seat truck enclosures
  • Under-seat bass systems
  • Center-console builds
  • Compact cars and hatchbacks
  • Custom motorcycle or powersports installations
  • Multi-subwoofer systems using several compact drivers
  • Customers who need real bass without a large enclosure

A compact subwoofer still needs the correct enclosure volume, mounting depth, amplifier power and crossover settings. Do not assume every 6.5-inch subwoofer will work properly in the same box.

Sky High FXB 8-Inch Subwoofer

The Sky High Car Audio FXB Series 8-inch subwoofer is rated for 600 watts RMS and is available with dual 2-ohm or dual 4-ohm voice coils.

The FXB 8-inch provides more cone area and power handling than the compact 6.5-inch model while remaining easier to fit than many larger subwoofers.

It can work well for:

  • Small and medium truck enclosures
  • Compact trunk systems
  • Hatchbacks and smaller vehicles
  • Single high-output 8-inch builds
  • Dual, triple or four-subwoofer installations
  • Customers wanting strong bass from limited space

Sky High FXB 10-Inch Subwoofer

The Sky High Car Audio FXB Series 10-inch subwoofer is rated for 1,000 watts RMS and is available with dual 2-ohm or dual 4-ohm voice coils.

The FXB 10-inch offers a strong balance between manageable enclosure size, responsive bass and serious output potential. It can be a practical choice for customers who want more authority than a compact 8-inch system without immediately moving to a large 12-inch, 15-inch or 18-inch enclosure.

Consider the FXB 10-inch for:

  • Loud daily-driver trunk systems
  • Truck enclosures with sufficient mounting depth
  • Single high-output 10-inch systems
  • Dual 10-inch bass builds
  • Ported enclosures designed for the exact subwoofer
  • Customers wanting strong output from a moderate-sized box

Sky High FXB 12-Inch Subwoofer

The Sky High Car Audio FXB Series 12-inch subwoofer is rated for 1,500 watts RMS and is available with dual 2-ohm or dual 4-ohm voice coils.

The 12-inch FXB is a strong all-around option for loud daily systems. It provides substantial power handling and cone area while remaining easier to fit than many 15-inch or 18-inch builds.

The FXB 12-inch can make sense for:

  • Single high-output 12-inch systems
  • Dual 12-inch trunk builds
  • Loud daily cars, trucks and SUVs
  • Street-demo-style systems
  • Customers wanting strong bass without using the largest available subwoofer
  • Builds supported by a properly matched amplifier and electrical system

Sky High FXB 15-Inch Subwoofer

The Sky High Car Audio FXB Series 15-inch subwoofer is rated for 1,500 watts RMS and is available with dual 2-ohm or dual 4-ohm voice coils.

The FXB 15-inch provides more cone area for customers who have enough vehicle space for the required enclosure and want deeper, heavier low-frequency output.

Consider the FXB 15-inch for:

  • Large trunk installations
  • Hatchback and SUV systems
  • Single 15-inch ported builds
  • Dual 15-inch systems
  • Loud daily and street-demo-style installations
  • Customers prioritizing deep bass and increased cone area

A 15-inch subwoofer requires enough room for more than the basket. The installation also needs the correct internal enclosure volume, port area when applicable, cone clearance and room for the enclosure to load properly inside the vehicle.

Sky High FXB 18-Inch Subwoofer

The Sky High Car Audio FXB Series 18-inch subwoofer is rated for 1,500 watts RMS and is available with dual 2-ohm or dual 4-ohm voice coils.

The FXB 18-inch offers the greatest cone area in the series and is intended for builds with enough room for a properly designed large enclosure.

The FXB 18-inch can work well for:

  • Large SUV and hatchback systems
  • Wall and no-wall bass builds
  • Single high-output 18-inch enclosures
  • Multiple 18-inch systems
  • Deep low-frequency daily systems
  • Street-demo-style builds
  • Customers with enough amplifier power and electrical support

An 18-inch subwoofer should not be forced into an enclosure that is too small simply because the basket fits. The enclosure, port, vehicle space and loading direction must all be planned around the exact subwoofer.

Choosing the Right FXB Subwoofer Size

The largest FXB subwoofer is not automatically the best choice. Begin by measuring the available space and deciding how much seating or cargo area can be dedicated to the enclosure.

Choose the 6.5-Inch FXB When:

  • Available space is extremely limited.
  • The enclosure must fit under or behind a seat.
  • You are planning a multi-subwoofer compact build.
  • Preserving passenger and cargo space is important.

Choose the 8-Inch FXB When:

  • You want compact dimensions with stronger output potential.
  • A 10-inch or larger enclosure will not fit properly.
  • You are building a truck, hatchback or compact trunk system.
  • You want to use multiple smaller subwoofers.

Choose the 10-Inch FXB When:

  • You want a balance between output and enclosure size.
  • You prefer a responsive daily bass system.
  • A 12-inch enclosure would use too much space.
  • You are planning a serious single or dual 10-inch build.

Choose the 12-Inch FXB When:

  • You want a strong all-around loud-daily size.
  • The vehicle has enough space for the correct enclosure.
  • You are planning a single or dual high-output system.
  • You want substantial output without moving to a 15-inch or 18-inch model.

Choose the 15-Inch FXB When:

  • You have room for a larger enclosure.
  • Deep bass and increased cone area are priorities.
  • You are building in a large trunk, hatchback or SUV.
  • The vehicle can support the required enclosure and amplifier power.

Choose the 18-Inch FXB When:

  • You have substantial enclosure space available.
  • You want the greatest cone area in the FXB lineup.
  • You are planning a large SUV, hatchback, wall or no-wall build.
  • The amplifier, wiring and electrical system are being built around the subwoofer.

Dual 2-Ohm vs Dual 4-Ohm FXB Subwoofers

The dual 2-ohm and dual 4-ohm versions are not separate power levels. The voice-coil configuration determines the wiring options available and the final impedance presented to the amplifier.

For one dual-voice-coil subwoofer:

  • A dual 2-ohm model can normally be wired to a 1-ohm or 4-ohm final load.
  • A dual 4-ohm model can normally be wired to a 2-ohm or 8-ohm final load.

Using multiple FXB subwoofers creates additional wiring possibilities. Decide how many subwoofers will be installed and what impedance the amplifier needs before selecting the voice-coil configuration.

Never connect an amplifier below its minimum stable impedance. An unsafe final load can increase current demand and heat while causing protect mode, blown fuses or equipment failure.

Match the Amplifier to the FXB Subwoofers

Choose an amplifier by comparing its rated RMS output at the completed impedance with the combined RMS rating of the FXB subwoofers.

Before selecting an amplifier, confirm:

  • The RMS rating of each subwoofer
  • The dual 2-ohm or dual 4-ohm configuration
  • The number of subwoofers being installed
  • How the voice coils and subwoofers will be wired
  • The completed final impedance
  • The amplifier’s rated output at that impedance
  • The amplifier’s minimum stable load
  • The power wire, ground wire and fuse protection required
  • Whether the vehicle’s charging system can support the amplifier

Browse monoblock car audio amplifiers when planning power for a Sky High FXB subwoofer system.

The Correct Subwoofer Enclosure Matters

A powerful FXB subwoofer can still perform poorly in the wrong enclosure. The enclosure affects low-frequency extension, output, efficiency, cone control and how the system behaves inside the vehicle.

Before building or purchasing an enclosure, verify:

  • Recommended net enclosure volume
  • Sealed or ported enclosure requirements
  • Recommended tuning frequency when applicable
  • Required port area
  • Subwoofer displacement
  • Port and bracing displacement
  • Mounting depth
  • Cutout diameter
  • Surround and cone clearance
  • Available space and loading direction inside the vehicle

Do not select a box only because its cutout matches the advertised subwoofer size. Different subwoofers with the same diameter can require very different enclosure volumes and port designs.

Browse available subwoofer boxes and enclosures when planning the complete bass system.

Plan the Wiring and Electrical Support

As amplifier power increases, the power wire, ground wire, fuse protection, battery support and alternator capacity become more important.

Complete the installation with properly selected car audio amplifier wiring kits and review available Sky High Car Audio Big 3 kits when the charging and grounding paths need to support a larger amplifier system.

A Big 3 upgrade does not increase the alternator’s rated output. Larger FXB builds may still require stronger battery support or a high-output alternator depending on the amplifier demand and how the system will be used.

Set Gain, Crossovers and Filters Correctly

Amplifier gain is used to match the amplifier’s input sensitivity to the source signal. It is not an additional volume control. Excessive gain can create clipping, heat and damaged voice coils.

The low-pass crossover should keep unwanted upper frequencies out of the subwoofer system. A properly selected subsonic filter can also help protect FXB subwoofers in ported enclosures from excessive movement below the enclosure’s useful operating range.

Final settings should be based on the enclosure, tuning frequency, amplifier, signal source and operating range of the completed system.

Shop All Sky High Car Audio Subwoofers

Compare the FXB Series with FE Slim, FE, BMX, FMX and FXXL models in the complete Sky High Car Audio subwoofer collection.

Helpful FXB and Bass-System Guides

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