About the Focal Inside ISUB BMW4

Product highlights:
- single 8" 4-ohm component subwoofer
- designed for specific BMW models
- Polyglass woofer cone
- butyl rubber surround
- neodymium magnet
- power handling: 90 watts RMS (180 watts peak)
- frequency response: 35-200 Hz
- sensitivity: 83 dB
- grille not included
- warranty: 1 year
- MFR # ISUBBMW4
- Item # 091ISUBMW4
What's in the box:
Focal Inside ISUB BMW4 owner's manual
If you need assistance accessing this owner's manual, please give us a call.- 1 Subwoofer
- 1 Foam gasket
- Four 1" Screws
- User manual (English/ French/ German/ Italian/ Spanish/ Portugese/ Dutch/ Polish/ Russian/ Chinese/ Korean/ Japanese/ Arabic)
- Focal window sticker
- Adhesive backed Focal Inside badge
More details on the Focal Inside ISUB BMW4

Features & specs
General | ||
---|---|---|
Speaker Size | Vehicle-specific | |
Driver Design | 1-way | |
Woofer Design | Cone | |
Woofer Material | Polyglass/Paper | |
Woofer Surround | Butyl Rubber | |
Midrange Design | --- | |
Midrange Material | --- | |
Tweeter Design | --- | |
Tweeter Material | --- | |
Super Tweeter Design | --- | |
Super Tweeter Material | --- | |
Impedance (Ohms) | 4 | |
Weather-resistant | No | |
Grilles Included | No | |
Parts Warranty | 1 Year | |
Labor Warranty | 1 Year | |
Specifications | ||
Sensitivity (1W at 1 meter) | N/A | |
Sensitivity at 2.83 volts | 83 | |
Frequency Response | 35 - 0.2k Hz | |
Maximum RMS Wattage | 90 | |
Peak Power Handling (Watts) | 180 | |
Top-mount Depth (Inches) | 1 7/16 | |
Bottom-mount Depth (Inches) | N/A | |
Cutout Diameter or Length (inches) | 7 7/16 | |
Mounting Height (Inches) | 0.91 | |
Frame Width | 8.5 | |
Frame Length | 8.5 |
Product Research
Features
Mounting: The ISUB BMW 4 is a direct replacement for the factory under-seat subwoofers in select BMW models. In most cases, the new sub has the same screw hole pattern as the factory sub and is a perfect fit, but there are a few instances where the factory sub was glued in place and new screw holes need to be drilled in the plastic factory enclosure. The factory grille is re-installed over the new subwoofer. This sub is packaged individually, so you will need to purchase two. Please enter your vehicle information to confirm fit.
Wiring: The BMW factory wiring harness plugs directly into the subwoofer frame.
Polyglass Cone: The subwoofer cone has a cellulose pulp base and is coated with a uniform deposit of hollow glass microballs. The addition of the Polyglass layer significantly increases the cone's rigidity without adding much weight. This combination takes advantage of the accuracy and neutrality of the hard outer surface, but maintains the superior damping characteristics of the cellulose pulp. The subwoofer has a built-in cover, so the cone isn't visible during installation.
Magnets: The sub uses a neodymium magnet to minimize size without giving up magnetic field strength.
Reinstalling Seats: When researching a previous generation BMW replacement subwoofer, I found a warning about not reconnecting the battery until the seats have been reinstalled and the wiring reconnected. The warning stated that reconnecting power too soon, to test the new subs, can damage the seats and airbags. I found no such warning related to this ISUB BMW 4 sub, but to be safe I recommend heeding the warning in this case as well.
Loading...
Loading accessories...
Customer Q&A
Loading...
Loading articles...
Crtuchfield's customer service and return/exchange policy are excellent. Plus, the products I received are as described, and the installation manuals rock. I'm sure I saved at least a couple grand in stereo shop labor charges being able to upgrade my car's system myself.
Keith Kenneth from HOUSTON, TX