2018 Nissan Sentra Front Speaker Size

The 2018 Nissan Sentra, a popular compact sedan, offers a respectable level of audio performance from its factory-installed speakers. However, for many enthusiasts, the stock sound system leaves something to be desired. Upgrading the front speakers is a common and relatively straightforward way to significantly improve the listening experience. But before diving in, understanding the specific speaker size and related technical details for the 2018 Sentra is crucial for a successful installation.

Understanding Speaker Sizes: Not Just a Number

While a single dimension is often quoted as the "speaker size," it's essential to realize that this is an oversimplification. The stated size typically refers to the diameter of the speaker cone. However, numerous other dimensions play a vital role in determining whether a particular speaker will fit properly in the 2018 Sentra's front door or dashboard locations. These include:

Mounting Depth: The distance from the speaker's mounting surface (where it screws into the door) to the back of the speaker's magnet. If the mounting depth is too great, the speaker may physically interfere with the window mechanism or other components inside the door.
Flange Diameter: The overall diameter of the speaker's frame. A larger flange diameter might require trimming of the door panel or speaker adapter.
Bolt Circle Diameter (BCD): The diameter of the circle formed by the mounting bolt holes. Speakers with different BCDs will not be compatible with the factory mounting points.
Tweeter Protrusion (If Applicable): For component speaker systems (where the tweeter is separate from the woofer), the tweeter's protrusion can impact fitment, especially if it's mounted in a limited space on the dashboard.

Ignoring these dimensions can lead to frustrating installation issues and potentially damage your vehicle or the new speakers.

The 2018 Nissan Sentra Front Speaker Size: Nominal and Real

The 2018 Nissan Sentra utilizes a 6.5-inch (165mm) speaker in the front doors. This is the nominal speaker size. While a 6.5-inch speaker is generally the correct size, it's imperative to confirm compatibility using resources like Crutchfield's vehicle fit guide or by physically measuring the factory speaker before purchasing replacements.

It's also important to note that some manufacturers use slightly different terminology. You might see speakers advertised as 6-3/4 inch, which are generally compatible with 6.5-inch applications. However, always double-check the detailed dimensions before committing to a purchase.

Why 6.5-inch Speakers are Common

The 6.5-inch speaker size is prevalent in many modern vehicles because it offers a good balance between bass response, midrange clarity, and installation ease. Larger speakers (like 6x9 inch) can produce deeper bass but require more space and often compromise midrange performance. Smaller speakers (like 5.25 inch) are easier to fit but generally lack low-end punch. The 6.5-inch speaker hits a sweet spot, making it a popular choice for automotive manufacturers.

Speaker Mounting and Adapters

In most cases, replacing the front speakers in a 2018 Nissan Sentra will require the use of speaker adapters. These adapters are typically made of plastic or MDF (Medium-Density Fiberboard) and serve several crucial functions:

Bridging the Gap: The factory speaker mounting points on the door often don't align perfectly with the mounting holes on aftermarket speakers. Adapters provide a standardized interface for connecting the new speaker to the vehicle.
Improving Seal: Adapters can help create a tighter seal between the speaker and the door panel, preventing sound from leaking out the back and improving overall audio quality.
Providing Clearance: In some cases, adapters may be needed to provide additional clearance for the speaker's magnet or basket, preventing it from interfering with the door mechanism.

You can find vehicle-specific speaker adapters online from retailers like Crutchfield or Amazon. When selecting an adapter, make sure it's specifically designed for the 2018 Nissan Sentra to ensure proper fitment.

Some advanced installers even choose to create their own custom speaker adapters using MDF or other materials. This allows for greater flexibility in speaker selection and can optimize the speaker's performance by decoupling it from the door panel (reducing vibrations).

Wiring and Connections

Replacing the front speakers also involves connecting the new speakers to the vehicle's wiring harness. Cutting and splicing the factory wiring is generally not recommended, as it can damage the wiring and potentially void your vehicle's warranty. Instead, use speaker wiring adapters, also known as wiring harnesses.

These adapters plug directly into the factory speaker connectors and provide standardized connections for the new speakers. They make the installation process much easier and safer, and they allow you to easily revert to the factory speakers if needed.

Pay close attention to the polarity when connecting the speakers. Most speakers have markings indicating the positive (+) and negative (-) terminals. Connecting the speakers with the wrong polarity can result in phase cancellation, which will significantly degrade the sound quality, particularly in the bass frequencies. Typically, the positive wire is red or marked with a stripe, while the negative wire is black.

Component vs. Coaxial Speakers

When upgrading your front speakers, you'll typically have two options: coaxial speakers and component speakers.

Coaxial Speakers: These speakers have the tweeter (high-frequency driver) mounted directly in the center of the woofer (low-frequency driver). They are easier to install because they require only one mounting location and one set of wiring connections.
Component Speakers: These speakers have separate tweeters and woofers, allowing for more flexible placement. The tweeters can be mounted higher up in the door or on the dashboard, improving the soundstage and imaging. Component systems also often include external crossovers, which allow for more precise control over the frequencies sent to each driver.

For the 2018 Nissan Sentra, a component speaker system is generally considered the better option for achieving the highest possible sound quality. The ability to position the tweeters independently allows for a more realistic and immersive listening experience. However, component systems are typically more expensive and require more complex installation.

If you opt for a component system, you'll need to determine the best location for the tweeters. Common options include:

Factory Tweeter Locations (If Equipped): Some Sentra models may have factory tweeter locations in the A-pillars or dashboard.
Surface Mounting on the Dashboard: Tweeters can be surface-mounted on the dashboard using adhesive or mounting brackets.
Flush Mounting in the Door Panel: Tweeters can be flush-mounted in the door panel, requiring you to drill a hole.

Beyond Speaker Size: Other Considerations

While speaker size is a critical factor, it's not the only thing to consider when upgrading your front speakers. Other important aspects include:

Speaker Sensitivity: Sensitivity is a measure of how loud a speaker will play with a given amount of power. Speakers with higher sensitivity ratings will generally be louder than speakers with lower sensitivity ratings, even when powered by the same amplifier. If you're using the factory head unit to power your speakers, choose speakers with a higher sensitivity rating (e.g., 90dB or higher).
Power Handling: Power handling is the maximum amount of power that a speaker can safely handle. If you're planning to use an external amplifier, make sure the speakers' power handling is compatible with the amplifier's output.
Impedance: Impedance is a measure of a speaker's resistance to electrical current. Most car speakers have an impedance of 4 ohms. Make sure the impedance of your new speakers is compatible with your amplifier or head unit.
Speaker Quality: Ultimately, the quality of the speaker itself will have the biggest impact on the sound. Look for speakers from reputable brands and read reviews to get an idea of their performance.

Conclusion

Upgrading the front speakers in your 2018 Nissan Sentra can significantly improve your listening experience. While the nominal speaker size is 6.5 inches, it's crucial to consider other dimensions, such as mounting depth and flange diameter, to ensure proper fitment. Using speaker adapters and wiring harnesses will make the installation process easier and safer. And finally, don't forget to consider other important factors like speaker sensitivity, power handling, and overall speaker quality.

By taking these factors into account, you can select the perfect speakers for your needs and enjoy a vastly improved sound system in your 2018 Nissan Sentra.