2018 BMW M4 Speaker Sizes

The 2018 BMW M4 factory audio system features specific mounting locations that accept various audio components. Center dash, front door panel, rear, and rear side panel locations accommodate 1 inch speakers and 4 inch speakers, while below seats locations support an 8 inch speaker size. Compatible speaker types for replacement and upgrade projects include tweeters, midranges, and subwoofers.

Specific details regarding locations, speaker sizes, and types are outlined in the compatibility chart.

Speaker Details by Location
Location	Size	Type	Notes
Below Seats	8	Subwoofer	Very limited height clearance Medium replacement priority Replacement difficulty: medium
Center Dash	1	Tweeter	Requires dashboard disassembly Medium replacement priority Replacement difficulty: medium
Center Dash	4	Midrange	Requires dashboard disassembly Medium replacement priority Replacement difficulty: medium
Front Door Panel	1	Tweeter	Standard installation High replacement priority Replacement difficulty: low
Front Door Panel	4	Midrange	Standard installation High replacement priority Replacement difficulty: low
Rear	1	Tweeter	Secondary sound location Medium replacement priority Replacement difficulty: medium
Rear	4	Midrange	Secondary sound location Medium replacement priority Replacement difficulty: medium
Rear Side Panel	1	Tweeter	Requires trim removal Medium replacement priority Replacement difficulty: medium
Rear Side Panel	4	Midrange	Requires trim removal Medium replacement priority Replacement difficulty: medium

2018 BMW M4 Speaker Replacement Summary

9 total positions

2 easy to replace

2 high priority

0 professional only

Replacement difficulty:

Low: 2 Medium: 7 High: 0

Replacement priority:

High: 2 Medium: 5 Low: 2

Additional Notes

The 2018 BMW M4 factory audio system utilizes a multi-component speaker configuration with dedicated tweeters, midrange drivers, and subwoofers positioned throughout the cabin for distributed sound coverage.
Tweeters measuring 1 inch are installed in four locations including the center dash, front door panels, rear area, and rear side panels to handle high-frequency reproduction.
Midrange speakers at 4 inches occupy the same four locations as the tweeters, suggesting a component-style setup where frequencies are divided between separate drivers rather than using full-range coaxial speakers.
An 8-inch subwoofer positioned below the seats provides low-frequency output, which may be easier to upgrade than door-mounted speakers depending on accessibility and mounting requirements.
Aftermarket component speaker systems with separate tweeters and midrange drivers would maintain the factory configuration approach, though installation complexity increases compared to coaxial alternatives.
Sound quality improvements could come from replacing the 4-inch midrange drivers, as these handle the critical midrange frequencies where vocals and most instruments reside in the audio spectrum.
The tweeter locations in both front and rear positions indicate that the factory system attempts to create a balanced soundstage for occupants in all seating positions.
Upgrading the under-seat subwoofer might require attention to impedance matching and power handling specifications to work properly with the factory amplifier if one is present.