1999-2005 BMW 3 Series Subwoofer Box Fitment

1999-2005 BMW 3 Series E46 — subwoofer box fitment

What we researched for this specific generation: where an enclosure actually fits, what the factory speakers are, how the factory audio is wired, and which real builds and commercial products exist for it. Confidence badges say how well each figure is sourced — this is research, not manufacturer spec.

Body styles covered: 4-Door Sedan, 2-Door Coupe, 2-Door Convertible

Where a box actually fits

These are researched envelopes, not a guarantee. Measure your own vehicle — the numbers here tell you what to expect, not what you have.

Trunk Unconfirmed

Location	trunk, through existing opening (sedan)
Outer bounding box	No measured trunk dimensions found. Box facts (sedan only): mounting depth 7.50" 'based on 6" diameter magnet', 0.87 ft^3 per chamber ('Single cutout has one air chamber of 1.74 cu ft'), subs fire to the rear; no outside dimensions printed by either maker.

Door speaker fitment

Sizes and depths below are what research turned up for this generation. Confirm against your own vehicle before cutting or ordering — trim levels vary.

Front doors Unconfirmed

Factory speaker size	BMW sheets give counts only
Adapter bracket needed	unconfirmed

Factory audio integration

Factory amp / premium audio	BMW US 'Standard & Optional Features' sheets. 2000 3 Series (323i, 323Ci, 328i, 328Ci): standard 'Anti-theft AM/FM stereo radio/cassette audio system with 10 speakers, RDS & 3-channel diversity antenna system'; optional 'Harman Kardon anti-theft stereo radio/cassette audio system with 12 speakers (incl. 2 subwoofers) & vehicle speed sensitive equalization'. 2001 330 models (330i/xi sedan, 330Ci coupe, 330Ci convertible): standard 10 speakers; optional 'Harman Kardon audio system with upgraded speakers including subwoofer(s)'; the sheet adds 'speaker configuration & number of speakers vary according to model'. Subwoofer positions not stated. 2002-2005 not read.

Factory amp / premium audio

BMW US 'Standard & Optional Features' sheets. 2000 3 Series (323i, 323Ci, 328i, 328Ci): standard 'Anti-theft AM/FM stereo radio/cassette audio system with 10 speakers, RDS & 3-channel diversity antenna system'; optional 'Harman Kardon anti-theft stereo radio/cassette audio system with 12 speakers (incl. 2 subwoofers) & vehicle speed sensitive equalization'. 2001 330 models (330i/xi sedan, 330Ci coupe, 330Ci convertible): standard 10 speakers; optional 'Harman Kardon audio system with upgraded speakers including subwoofer(s)'; the sheet adds 'speaker configuration & number of speakers vary according to model'. Subwoofer positions not stated. 2002-2005 not read.

Mounting locations

Trunk Unconfirmed

trunk, through existing opening

EPA sedan luggage volume 11 cu ft (fueleconomy.gov, 325i, 2001, 2003 and 2005 agree). No BMW trunk figure read. Zenclosures says the box is 'installed directly through the trunk opening and slid under the rear dash'; Super Crew Sound's listing of the same box says only that it 'Installs easily through the trunk opening'. Coupe and convertible cargo not read. The only box found is for the sedan: no box maker found lists an E46 coupe, convertible or wagon box.

Builds and products found for this vehicle

Outside links. Some are commercial products, some are owner builds posted on forums — the label says which. We do not endorse any of them.

Zenclosures (sealed) off-the-shelf
1999-2005 BMW 3 Series Subwoofer Enclosure. Maker years 1999-2005 (the whole 1999-2005 range). 'Sedan Only (4dr)'. No outside dimensions printed. 'Volume Airspace per chamber -0.87^3' (unit not printed). Mounting depth 7.5" 'based on a sub with a 6" diameter magnet'. Style sealed. Chambers 1 per sub. Hole 9 1/8" for 10" subs, 11 1/8" for 12" subs. 0.75" MDF, carpet. 'installed directly through the trunk opening and slid under the rear dash'. Super Crew Sound sells the same box as "BMW 3 Series Sedan Subwoofer Enclosure 1999-2005" (SKU 99bmw3series): same years, body, volume and mounting depth (its page does not say sealed). Details as printed on that page: '.87 cubic feet Per Sub'; 'Single cutout has one air chamber of 1.74 cu ft'; two separate air chambers; 'Subwoofers fire towards the rear'; cutout options dual, single centre, single driver side or single passenger side; 10" and 12"; round or square (Kicker L5/L7) cutouts; 'Installs easily through the trunk opening'.

Build it for this vehicle

Design a box for this vehicle — Enclosure volume, port tuning, and a see-through render.
Door speaker fitment — No measured door depth on file for this vehicle yet, so there is no fit check to run. The page says how to request one.
See the factory speaker locations — Factory speaker sizes, depths and locations we have researched for this vehicle.

Each link opens the tool with this vehicle already selected.

Before you cut anything

Measure your own vehicle. Trim levels, factory subwoofer options, and mid-generation changes all move these numbers, and a box cut to a researched figure that does not match your truck is wasted wood. Where a badge reads Unconfirmed, treat the value as a starting point for your own measurement, not as an answer.