Focal ISUB BMW Inside Series Direct Fit Subs Under Seat Subwoofers 4ohm
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The Focal ISUB BMW 4 is a pair of 8-inch, 4-ohm passive under-seat subwoofers from Focal's Inside Series, designed as direct-fit replacements for BMW and MINI vehicles with no cutting or modification required.
This listing is the pair. The ISUB BMW 4 is also available as a single subwoofer. Other impedances: ISUB BMW 2 (2 ohm) and ISUB BMW 8 (8 ohm).
Key specifications
- Type: pair of 8-inch under-seat subwoofers
- Impedance: 4 ohms (each)
- Power handling: 90W RMS / 180W peak (each)
- Sensitivity: 83dB
- Frequency response: 35Hz–200Hz
- Cone: Polyglass with butyl rubber surround
- Magnet: neodymium
- Grilles: not included
Pair of subwoofers
The ISUB BMW 4 drops straight into the original under-seat location in your BMW or MINI, delivering a serious bass upgrade. A neodymium motor keeps the design compact without compromising output.
Focal Inside for BMW & MINI
The Inside Series is built around hassle-free fitment. A spacer integrated into the chassis ensures perfect alignment with the original mounting location, and at 4 ohms the ISUB BMW 4 works directly with your factory amplifier — no wiring changes needed.
- Quick installation with mounting accessories included
- No wires to cut, no vehicle modification required
- 100% compatible with original vehicle locations
- Superior sound quality over the original fitment
If you're also looking to upgrade your door speakers, Focal's IC BMW 100L Inside Series coaxial speakers are designed for the same direct-fit BMW and MINI integration.
Explore the full range in Focal Inside.
Specification
| power handling | 90 watts RMS (180 watts peak) |
|---|---|
| frequency response | 35-200 Hz |
| sensitivity | 83 dB |
More specs
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What's Included
- 2 Subwoofer
- 2 Foam gasket
- Four 1" Screws
- User manual
- Focal window sticker
- Adhesive backed Focal Inside badge
Focal
About the Focal ISUB BMW 4 PAIR
From our tech experts at CEN
The Focal ISUB BMW 4 is a pair of 8-inch, 4-ohm passive under-seat subwoofers from Focal's Inside Series, designed as direct-fit replacements for BMW and MINI vehicles. Each unit handles 90W RMS, features a Polyglass cone with butyl rubber surround and neodymium magnet, and covers 35Hz to 200Hz at 83dB sensitivity.
Who it suits
These suit BMW and MINI owners wanting a bass upgrade without cutting or modifying the car. At 4 ohms, each sub works with the factory amplifier and drops into the original under-seat location with no wiring changes. If your vehicle is not a BMW or MINI, the Focal ISUB Twin is a compact passive underseat alternative.
Our tech experts advise
Always confirm your specific BMW or MINI model is compatible before ordering — contact us to check. The included foam gaskets and screws are all you need for installation. Note that grilles are not included with this listing. Fitting is priced per vehicle; see our Nottingham car audio installation page for details.
Explore the full Focal range at CEN, with fast UK dispatch and expert advice from our Nottingham team. Shop all Focal
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Have it Fitted By Our Team
Our team fits car audio, stereos, dash cams and vehicle security at our workshop in Beeston, Nottingham. Tell us your vehicle and we'll confirm the parts and a fitted price.
- 1
Tell us your vehicle
Make, model and year, and what you'd like fitted.
- 2
We confirm the parts
Fascia, wiring and interfaces checked for your car, with a fitted price.
- 3
Fitted at our workshop
Bring it to our Beeston workshop and we do the rest.
Unit 25 Technology Drive, Beeston, Nottingham NG9 1LA
Plug & Play Kits
Configure the solution best suited to your needs in just a few clicks.
Focal Inside Series
The Focal Inside offer is aimed at all drivers wishing to replace their car's original system with a hi-fi quality Plug & Play solution that integrates easily, without modifying the interior. Different configurations are available by brand (over 50 brands), by car model (1000 vehicle models).
Focal Car Audio
Deliver exceptional sound clarity and precision for your vehicle.
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Frequently Asked Questions
Q: What does RMS power mean?
A: RMS is the continuous power a subwoofer can handle, and it is the number that matters when matching an amplifier. Peak or max figures describe short bursts only. Match your amplifier output to the RMS rating in the Specification tab.
Q: Can CEN build or supply an enclosure and fit everything?
A: Yes. CEN supplies enclosures and offers professional installation from our Nottingham premises, including amplifier wiring. Contact us to discuss your build.
Q: How many subwoofers are in this ISUB BMW 4 listing?
A: Two. This listing is a pair, with two subwoofers and two foam gaskets, plus screws, a user manual, a Focal window sticker and an adhesive-backed Focal Inside badge.
Q: Do the ISUB BMW 4 subwoofers work with the factory amplifier?
A: Yes. At 4 ohms they are designed to work directly with the factory amplifier and fit the original under-seat locations.
Q: What power do the ISUB BMW 4 subwoofers handle?
A: Each subwoofer handles 90W RMS (180W peak), with a frequency response of 35Hz to 200Hz.
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