2018 Audi A4 Speaker Sizes and Audio System Guide
2018 Audi A4 Speaker Sizes and Audio System Guide
This page covers the factory speaker layout, common speaker locations, and upgrade notes for the 2018 Audi A4. Equipment can vary by trim, body style, or audio package, so some speakers and features may only appear on certain builds. Factory amplifier details should be verified by trim and audio package, and selected audio systems may also include optional tweeters, a subwoofer, or a center channel.
Data verified by Nick Marchenko, PhD
Speaker Size Chart – 2018 Audi A4
Use this table as the main reference. Fitment depends on trim, factory audio package, mounting depth, and adapter availability.
| Location | Type | Factory Size | Note |
|---|---|---|---|
| Front Pillar | Tweeter | 1 inch | if equipped |
| Rear Deck Corner | Mid-Range | 3.5 inch | |
| Rear Deck Corner | Subwoofer | 8 inch | if equipped |
| Front Door | Mid-Range | 3.5 inch | |
| Front Door | Full-Range | 6.5 inch | |
| Dash Corner | Tweeter | 1 inch | if equipped |
| Rear Door | Tweeter | 1 inch | if equipped |
| Rear Door | Full-Range | 6.5 inch | |
| Center Dash | Center Channel | 1 inch | if equipped |
| Center Dash | Center Channel | 2.5 inch | if equipped |
Generic speaker location diagram. The table above shows the specific factory sizes for this vehicle. Exact location details may vary by body style and trim.
Speaker Count by Trim – 2018 Audi A4
Speaker count and audio equipment vary by trim and factory audio package. This table lists known configurations from our database.
| Trim | Speakers | Amplifier | Radio | Navigation |
|---|---|---|---|---|
| 2.0T ultra Premium 4dr Front-wheel Drive Sedan | 10 | 180W | AM/FM/HD/Satellite-prep, seek-scan | ✓ |
Data sourced from manufacturer specifications. Verify with the window sticker or dealer before ordering audio components.
Vehicle and Audio System Specifications
This block helps identify the vehicle and its audio system configuration for fitment decisions.
Body Style Audio Differences
This 2018 Audi A4 uses the same core speaker layout across the available body styles in the database, but rear audio packaging and factory options can still vary. Different body styles may affect rear speaker placement, cargo-area acoustics, and whether optional tweeters, a center channel, or a subwoofer are included. Factory amplifier details should be verified by trim and audio package.
What Speakers Fit the 2018 Audi A4?
Aftermarket fitment should start with the factory speaker locations listed above, but diameter alone is not enough. Check mounting depth, bracket fit, connector type, and whether the vehicle has a premium or factory-amplified audio system. This 2018 Audi A4 uses a mix of 6.5-inch, 3.5-inch, and 1-inch speaker locations, and selected audio systems may also include a subwoofer if equipped. Factory amplifier details should be verified by trim and audio package.
Usually Safe Upgrades
- If your vehicle uses the front door 6.5-inch location, that is a common place to start when comparing aftermarket full-range speakers.
- If your vehicle uses the rear door 6.5-inch location, replacement full-range speakers in that size are the first fitment check.
- If your vehicle uses the front door 3.5-inch location, compact mid-range speakers in that size should be matched carefully to the factory opening.
- If your vehicle uses the rear deck corner 3.5-inch location, look for speakers that match both the diameter and the available mounting depth.
- If your vehicle uses a 1-inch tweeter location, such as the front pillar, dash corner, or rear door, replacement tweeters should be matched to the factory opening if equipped.
Check Before Buying
- Confirm the exact speaker location before ordering, since this model uses multiple factory sizes.
- Measure mounting depth and grille clearance, especially for the 6.5-inch and 3.5-inch locations.
- Verify connector style and mounting hardware, because factory brackets and plugs can affect installation.
- Check whether the vehicle has a premium or factory-amplified audio system, since that can change speaker compatibility and system tuning.
- If the vehicle has the optional 8-inch subwoofer, confirm the enclosure and wiring before choosing a replacement.
Installation Notes
The 2018 Audi A4 uses a 10-speaker layout on the listed trim, and equipment can vary by audio package. Front pillar tweeters, dash corner tweeters, rear door tweeters, and the center dash speakers are only present if equipped, while the rear deck corner subwoofer should be treated as optional. Plan on careful panel removal to avoid damaging clips, trim, and surrounding surfaces. Before disconnecting anything, verify speaker location, size, and connector style at each opening because factory wiring and speaker depth can affect fitment. Mounting adapters may be needed for the 6.5-inch and 3.5-inch locations, and harness adapters can help preserve the factory connections. If your vehicle has the factory subwoofer, confirm enclosure clearance and polarity before installation. After everything is installed, test each speaker individually for balance, fade, and any rattles before reassembling the panels.
Moderate difficulty, since access, wiring, and speaker depth should all be checked carefully before installation.
Common Mistakes When Replacing Speakers
Here are the most common mistakes people make when shopping for speaker upgrades for the 2018 Audi A4.
- Buying based only on the body-style label instead of checking actual speaker locations on the vehicle.
- Skipping trim and audio package verification, even though factory amplifier details should be checked by trim and audio package and the listed 180W setup applies only to the trim shown.
- Ignoring speaker size and mounting depth, which can cause fitment problems with the 1 inch, 2.5 inch, 3.5 inch, 6.5 inch, and 8 inch locations listed for this model.
- Assuming every speaker position is the same across the car and overlooking that tweeters, the subwoofer, and the center channel may be included only if equipped.
- Not checking connector style before ordering parts, which can lead to wiring mismatches even when the speaker size looks correct.
- Reassembling everything before testing the system, instead of confirming each speaker plays correctly and the balance sounds right while access is still easy.
Generation & Model Family
The 2018 Audi A4 belongs to the Fifth generation (B9) (2017–2019) family. Nearby model years often share similar speaker locations and audio layouts, but exact fitment can vary by trim and audio package – verify before ordering.
Recommended Upgrade Path
The 2018 Audi A4 in the B9 generation uses a 10-speaker layout on at least some trims, and equipment can vary by audio package. Front-stage upgrades are usually the best place to start if you want cleaner detail, stronger vocal presence, or a more balanced system. Factory amplifier details should be verified by trim and audio package before planning larger upgrades.
| Goal | Best Upgrade Path | Why |
|---|---|---|
| Better clarity | Upgrade the front door speakers first, then add better front tweeters if equipped, so the front stage delivers cleaner mids and highs. | Clarity improvements usually come from the speakers you hear most. A stronger front stage helps restore detail and improve imaging without changing the whole system at once. |
| More bass | If the factory subwoofer is equipped, treat it as a starting point and add an aftermarket subwoofer solution to increase low-end output. | The listed rear-deck subwoofer may be trim-dependent, so bass upgrades should be planned around the existing system. Adding dedicated low-frequency support gives more impact than relying on the stock speakers alone. |
| Louder sound | Properly matched speakers and amplifier integration can improve volume and reduce distortion. Verify factory amp and premium system integration before adding aftermarket amplifiers. | Higher volume needs clean power and compatible signal integration. Matching the speakers to the amplifier helps the system play louder while staying controlled. |
| Budget improvement | Replace the front door speakers first with same-size replacement speakers with correct mounting brackets. | The front doors handle the most important everyday listening. Starting there gives the best return for a modest budget and keeps the upgrade focused on the speakers you use most. |
| Factory look | Use same-size replacement speakers with the correct mounting brackets and harness adapters for a clean install that preserves the factory wiring and appearance. | This approach keeps the cabin looking original while still improving sound. It also helps the upgrade stay tidy and reversible if you ever change the system later. |
Mounting Adapters and Wiring
The same nominal diameter does not guarantee a direct mount. Before ordering, confirm:
- Speaker depth: Aftermarket speakers often have larger magnets – measure available depth at each location.
- Mounting brackets: Door locations typically need a bracket or spacer to clear the window regulator and achieve correct mounting depth.
- Wiring harness adapters: Use a plug-and-play harness adapter to preserve factory wiring.
- Tweeter mounting cups: Replacing OEM tweeters may require surface-mount cups or brackets depending on the location.
- Factory or premium amplified systems: If the vehicle has a premium or factory-amplified audio system, confirm how the factory radio, amplifier, and speakers are connected before adding aftermarket amplifiers. Depending on the setup, a line output converter, DSP, integration harness, or professional installation may be needed.
- Connector type: Factory connectors vary by trim and model year – confirm compatibility before splicing or using an adapter.
Frequently Asked Questions
What front door speaker size does the 2018 Audi A4 use?
The front door speakers are 6.5 inches for the full-range position and 3.5 inches for the mid-range position. Tweeter locations may also be present if equipped.
What size speakers are in the rear of the 2018 Audi A4?
The rear door uses 6.5-inch full-range speakers, and the rear deck corner uses 3.5-inch mid-range speakers. A rear subwoofer may also be included if equipped.
Does the 2018 Audi A4 have a factory subwoofer?
A factory 8-inch subwoofer is listed, but it may be trim-dependent and should be verified by audio package. It is only present if equipped.
Do I need mounting adapters to replace the speakers?
Mounting adapters may be needed depending on the speaker location and the replacement speaker design. Check the exact opening size before choosing new speakers.
Can I replace the speakers without replacing the radio?
Yes, speaker upgrades can be done while keeping the factory radio. The best results depend on speaker compatibility and whether the system includes an amplifier.
Does the 2018 Audi A4 have a factory amplifier?
Factory amplifier details should be verified by trim and audio package. One listed trim includes a 180W amplifier, but that setup is not universal.