What the Kenwood Excelon DMX1057XR does in a Scion xB

The Kenwood Excelon DMX1057XR is a 10-inch powered subwoofer designed to sit in the cargo area of a Scion xB and connect to your car's audio system through the amplifier or head unit. It produces low-frequency bass that your factory speakers cannot deliver on their own. The unit comes pre-amplified, meaning it has its own built-in power supply and does not require a separate amplifier to operate — you run a single cable from your head unit to the subwoofer, and it handles the rest.

In a Scion xB, this subwoofer fits the available space without requiring custom fabrication or removal of seats. The xB's boxy shape and flat cargo floor make it one of the more straightforward vehicles for subwoofer installation. The DMX1057XR will improve music clarity across all genres and make movies or podcasts sound fuller when played through your car's audio system.

Key Takeaways

  • The Kenwood Excelon DMX1057XR is a powered subwoofer that mounts in your xB's cargo area and connects with a single cable to your head unit.
  • You will need a remote level control wire, RCA cables, a power cable run through the firewall, and a ground wire attached to the chassis to complete the installation.
  • The subwoofer draws power from your car's battery, so you should run the power cable through a fused distribution block to protect your electrical system.
  • Tuning the subwoofer's crossover frequency and volume level happens through controls on the back of the unit or via a wireless remote you can purchase separately.

Tools and materials you will need before starting

Gather these items before you begin: a socket set and screwdrivers (Phillips and flathead), wire strippers, a crimper for making terminal connections, electrical tape, a fuse holder with inline fuse (typically 60 to 80 amps for this unit), RCA cables (shielded, at least 18 feet to reach from the front of the car to the cargo area), a remote turn-on wire (also called a remote level control wire), a power cable rated for the subwoofer's amperage draw, and a ground cable of similar gauge.

You will also need a location to mount the subwoofer securely. Most Scion xB owners place the unit on the cargo floor against the rear seats or in the corner, using the mounting bracket that comes with the Kenwood unit or a custom enclosure. A drill with bits may be necessary if you are fastening the bracket to the floor. Do not skip the fuse holder — it protects your car's electrical system if a wire shorts.

Running power and ground cables through your xB

The power cable must run from your car's battery, through the firewall (the metal barrier between the engine and cabin), and into the cargo area where the subwoofer sits. Start by locating the firewall grommet — a rubber-lined hole already present in most vehicles for passing wires. If your xB does not have an accessible grommet, you can drill a small hole and install a rubber grommet yourself to protect the wire from the sharp metal edges.

Run the power cable from the positive terminal of your battery, through the firewall, and along the interior of the car to the subwoofer. Install the fuse holder within 18 inches of the battery — this is a safety requirement. The ground cable should run from the negative terminal of the battery (or a nearby ground point on the engine block) to a clean, unpainted metal surface on the chassis near the subwoofer. Sand away any paint at the ground point to may support solid contact. A loose ground connection is the most common cause of noise or power issues.

Connecting RCA and remote wires from your head unit

The RCA cables carry the audio signal from your head unit to the subwoofer. Run these cables along the opposite side of the car from the power cable — this separation reduces electrical noise. If your factory head unit does not have RCA outputs, you will need a line output converter (LOC) that taps into the speaker wires and converts them to RCA level signals. Many aftermarket head units have RCA outputs built in.

The remote turn-on wire (a thin wire, usually blue) connects from your head unit to the subwoofer's remote input. This wire tells the subwoofer to power on when you turn on the head unit and power off when you turn it off. Without this wire, the subwoofer will draw power constantly and drain your battery. Run this wire alongside the RCA cables, not with the power cable.

Mounting and securing the subwoofer in the cargo area

Position the Kenwood Excelon DMX1057XR on the cargo floor of your xB. The unit comes with a mounting bracket and feet designed to keep it stable during acceleration and braking. find the subwoofer using the bolts provided, fastening it to the floor or to the bracket. Make sure the subwoofer does not block the rear door from opening fully or interfere with the spare tire or jack if you keep those in the cargo area.

Once mounted, connect the power cable, ground cable, RCA cables, and remote wire to the terminals on the back of the subwoofer. Double-check that all connections are tight and that no bare wire is exposed. The subwoofer should sit level and not rock or shift when you press down on it.

Adjusting crossover and volume settings

The back panel of the DMX1057XR has a crossover frequency dial (usually ranging from 50 Hz to 200 Hz) and a volume knob. The crossover frequency determines which sounds the subwoofer reproduces — lower settings mean the subwoofer handles only the deepest bass, while higher settings mean it also handles mid-bass. For most music and movies, a setting between 80 Hz and 120 Hz works well.

Start with the volume knob at the lowest setting. Turn on your head unit and play music you know well. Gradually increase the subwoofer volume until the bass feels balanced with the rest of the music — you should hear it, not feel overwhelmed by it. If you hear distortion or the subwoofer seems to cut out, lower the volume slightly. You can also purchase a wireless remote control for the Kenwood Excelon line that lets you adjust volume from the driver's seat without reaching the back of the car.

Troubleshooting common installation issues

If the subwoofer does not power on, check that the remote turn-on wire is connected and that your head unit is sending power to that wire. Use a multimeter to test for voltage at the remote input. If there is no voltage, the head unit may not have a remote output — you will need a line output converter with a remote output built in.

If you hear a hum or buzz, the ground connection is likely loose or corroded. Disconnect the ground cable, sand the connection point on the chassis until bare metal shows, and reconnect. If the hum persists, move the RCA cables away from the power cable — they may be running too close together and picking up electrical noise. If the subwoofer cuts out during loud passages, lower the volume setting or adjust the crossover frequency lower. Clipping (distortion) can damage the subwoofer over time.

Frequently Asked Questions

Will the Kenwood Excelon DMX1057XR fit in my Scion xB without removing seats?

Yes. The subwoofer is designed to sit on the cargo floor, and the xB has enough depth and width to accommodate it without interfering with passenger seating. You may lose some cargo space behind the rear seats, but the vehicle remains fully functional.

Do I need to upgrade my car's electrical system for this subwoofer?

The DMX1057XR draws moderate power and does not typically require a full electrical upgrade in a Scion xB. However, if your battery is old or your alternator is weak, you may notice dimming headlights during heavy bass. A new battery or a higher-output alternator can prevent this, but most xB owners do not need either one.

Can I use the factory head unit, or do I need to replace it?

The factory head unit in most xBs can work with the subwoofer if it has RCA outputs or if you install a line output converter. If your factory head unit has neither, you will need to replace it with an aftermarket unit that has RCA outputs or a built-in subwoofer output.

What happens if I run the power cable and RCA cables together?

Running them together can cause a hum or buzz in the subwoofer because the power cable generates electrical noise that the RCA cables pick up. Separate them by at least a few inches, or run them on opposite sides of the vehicle. This is one of the most common causes of noise in car audio systems.

How do I know if the subwoofer is installed correctly?

The subwoofer should power on when you turn on the head unit and power off when you turn it off. Bass should sound clean and not distorted, and the volume should be adjustable without cutting out. If you hear hum, buzz, or distortion, or if the subwoofer does not respond to volume adjustments, check the ground connection and cable routing first.