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Can Car Speakers Share a Common Ground

A ground wire is as important as a signal wire because, without the connection to the battery, the audio will not work.

An interconnection of electrical components in a closed loop is necessary to give the current a safe and clear path to travel. But can car speakers share a common ground? Let’s find out.

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In general, car speakers can share common ground if connected to an amplifier or receiver with a single-ended output. However, if the car speakers are connected to the amplifier with a bridged mode, they cannot share a common ground.

Also, when one amplifier powers the front speakers and another is for the rear speakers, you want to make sure that each has its own separate ground. Otherwise, the shared ground can cause a ground loop which can cause interference in an audio signal.

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Tip: It is best to keep each speaker on its own ground wire back to the battery for the most precise sound. But if you must share a common ground between two speakers, make sure they are the same size.

It is also important that the wires are the same gauge or thickness. Otherwise, one speaker will get more power than the other, causing the other one to play louder than the other and its thin wire to overheat.

In the article below, I will go into detail about how to wire car speakers to an amplifier.

What Is a Speaker Wire?

A wire carries electricity, and the amount of electrical current that can flow through is determined by the wire’s size. The gauge is determined standardized by the American Wire Gauge (AWG) and the British Standard Wire Gauge (SWG), both are known internationally, but the AWG is more widely utilized. 

An electrical audio wire is made of copper and is sheathed in a jacket that is sometimes insulated. Copper wiring is created at different performance levels, but the most often used car speaker wire is purity copper, produced to generate less oxygen. Oxygen-free copper (OFC) contains less distortion; therefore, it is the preferred wire for audio. Otherwise, the cheaper copper-covered aluminium wire is used.

can car speakers share a common ground

A cable is multiple wires encased in an electrical wire sheath or jacket. Typically they are color-coded, black for ground wires. It’s best to double-check the manufacturer’s specifications when buying cable because they are not obligated to comply with color standards but instead follow an industry specificity. 

The Internet contains many speaker wire charts, but Sonic Electronix has published a chart on their website entitled Wiring Harness Color Standards that indicates, black is normal for a ground wire. 

Additionally, solid versus stranded wire is considered in deciding the type of wire to purchase. Solid wire is not as flexible and can more easily break during installation or due to the music’s continuous vibrations. Stranded wire is bundled thin copper wire in a sheath, which is more pliable altogether.

What Is the Ground Wire?

The ground is an electrical path to prevent electric shock and reduce noise from electronics. If there is a fault in the normal circuitry path, an extra current will go to the ground; therefore, some current may flow through the ground wire.

It is a common misconception that neutral and ground wires are the same, but a neutral wire is grounded, but a ground wire is not necessarily neutral. Ground and neutral are not interchangeable. Neutral is normally non-current carrying unless there is a failure in the electrical system, in which case the current may get routed to the neutral wire.

While grounding is used to power the speaker while also maintaining the system’s fire safety and electrical safety in its entirety.

If you are looking for a place in your vehicle to ground your wire, for instance, the bracket behind a factory-installed radio, verify it’s appropriate using a multimeter instrument, which can measure voltage, resistance, and current. Just because it is metal doesn’t mean it’s a good grounding location.

The book Auto Audio by Andrew Yoder on includes a section on wiring and covers planning the system, grounds, and tracing ground problems. Although published several years ago, the wiring basics have not changed; therefore, the book is informative on this topic.

Or, in this 6-minute video by PS Audio, a common ground wire is defined. It is a quick and easy to understand tutorial:

Process and Prevention

Connecting multiple components to a common ground entails a few time-honored practices. Common ground should be placed as close to the components as possible, no more than 18 inches (45.72 cm) apart. It should also consist of bare metal wire connected with a crimp ground ring and a star washer to be sure close contact is made to resist the possibility of vibration.

Bare Wires, Crimp Connectors, and Star Lock Washers Explained

A bare wire, in this instance, is a copper wire without insulation. Although ground wire options are plentiful, Amazon carries the GS Power 100% Copper OFC Wire, 10 AWG, which is 25-feet (82 meters) of pure copper wire with red and black flexible jackets for easy installation. As always, it’s important to carefully read the specifications to be sure you are getting the proper quality wire for your audio system.

Notwithstanding, many types of crimp connectors are sold on For instance, the Hilitchi Automotive Electrical Wire Connectors Kit includes all sizes and types. Depending on your audio system design, the proper fit will be determined.

As with crimp connectors, the Hilitchi Stainless Steel Star Lock Washers sold on include all sizes. Choose the appropriate size for your design, keeping in mind their purpose, to maintain a tight connection.

From an engineer’s perspective, watching this informative 10-minute video on crimp ring terminals is a thorough demonstration of matching the correct parts for a valid connection:

Ground Loops Explained

Ground loops are the most often cause of noise interference and occur when two components are grounded in different places creating an unwanted current.

The underlying reason for the conflict is that ground has two different functions:

  • preventing electric shock.

To avoid or fix the whining or humming noises, break the ground loop. The system should connect to one single point grounding.

Reduce Noise

While the best ground is metal, plan the design before hooking up and installing the car audio for a best-case scenario. For example, grounding one audio component to the vehicle frame or chassis and another to the lighter could cause a ground loop. A preventative measure is to attach all audio component grounds to the vehicle frame at the same location. 

When dealing with existing noise interference, disassembling your stereo, locating the grounds, and putting it back together is recommended. If that isn’t feasible or the problem cannot be found and fixed, try patching it with an in-line noise filter.

A ground loop isolator works because there is no direct electrical connection between the audio input and output. The audio enters the isolator, passes through a transformer, and then exits the device; thus, interference is isolated from the input/output signal.

Although there are many types of noise isolators, in my opinion, the best that also has a 5-star on Amazon is the BESIGN Ground Loop Noise Isolator for Car Audio/Home Stereo System, which boasts musical clarity, portability, and plug and play capabilities.

Prevent Shock

As part of car maintenance, with the audio system turned off, occasionally check ground wire connections for corrosion or loosening. To prevent corrosion in the first place, brush on a light coating of silicone caulk to seal out the formation of moisture. Remember, don’t remove ground wire when the system is on due to sparking and potential damage to the components. 

Final Thoughts

Reducing whining or humming creates a silent backdrop and increases the dynamic musical range in a car audio system. Ground loop issues can be prevented by properly grounding wires to the chassis in one location. Still, in the event an existing problem can’t be mitigated, an isolator can be attached.

Consequently, in the quest for quiet, quality car audio, the stereo components should share a common ground.