Focal ISUB Active 2.1 Compact Underseat Car Subwoofer with 2 Channel Amplifier
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The Focal ISUB Active 2.1 is an ultra-compact amplified underseat subwoofer featuring an 8-inch (20 cm) driver and a built-in 2-channel amplifier, delivering 130W RMS (260W max) of bass plus 2 x 55W RMS to power front speakers — part of Focal's ISUB Active range.
This listing is for the ISUB Active 2.1. The ISUB Active range is also available as the ISUB Active (single-channel amplifier version).
Key specifications
- Subwoofer: 8" (20 cm) ultra-compact amplified underseat subwoofer
- Subwoofer power: 130W RMS (260W max)
- Built-in amplifier: 2 x 55W RMS (2 x 110W max) at 4Ω
- Frequency response: 45Hz – 150Hz
- Impedance: 4Ω
- Dimensions (L x W x H): 328 x 230 x 63 mm
- Weight: 4.25 kg
ISUB Active 2.1: amplified subwoofer with 2-channel amp
The ISUB Active 2.1 completes a factory audio system by adding powerful, dynamic bass and amplifying the vehicle's front channels (2.1 configuration). It connects directly to the car radio's speaker outputs via the supplied Plug & Play ISO cable — no boot space required, no cabin clutter.
At just 63 mm (2.5") tall, it slides under most seats, including tighter-fitting ones. Adjustable settings let you tune the sound to your preference, and a wired remote control is included for on-the-go bass level adjustment.
Key points
- Focal engineering and expertise
- Built-in 2-channel amplifier
- ISO Plug & Play cable supplied — ready to use straight away
- Ultra-compact at 63 mm high for discreet underseat fitment
- Adjustable input signal, crossover, and volume boost settings
- Wired remote bass controller included
- Robust construction
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Specification
| Type | 8" ultra-compact amplified subwoofer & 2-channel amplifier |
|---|---|
| Max. power | 260W |
| Nom. power | 130W RMS |
| Frequency response | 45Hz - 150Hz |
| Impedance | 4Ω |
| Fuse rating | 35A |
| Subwoofer phase | 0 or 180° |
| SNR | > 80dBA |
| Maximum power amplifier | 2 x 110W |
| Nominal power amplifier | 2 x 55W RMS |
| Impedance | amplifier 4Ω |
| Dimensions | (L x W x H) 328 x 230 x 63 mm |
| Weight | 4.25 kg |
What's Included
- Focal ISUB Active 2.1
- Wiring Kit
- Bass Controller
*Check the available space before the installation.
Focal
About the Focal ISUB Active 2.1
From our tech experts at CEN
A Focal active subwoofer with amplification built in, sized for an underseat or footwell location, so bass arrives from one unit rather than a separate sub, amp and box.
Who it suits
Drivers who want more low end without rebuilding the system or giving up the boot. Compact active units are the sensible answer where space is the binding constraint.
Our tech experts advise
It still needs a fused feed from the battery and a signal source, and level and crossover want setting against your existing speakers so it fills in underneath rather than announcing itself. Installation is priced per vehicle, so get in touch with your make, model and year and we will confirm what it needs. See car audio installation.
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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.
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Focal Car Audio
To combine the pleasure of driving with the love of sound, make sure your car is fitted with quality hi-fi equipment. Focal high-fidelity sound promises sensational musical emotions to enhance every journey.
Speaker Kits
With Focal's dedicated car speakers, take advantage of a wide choice of models to compose your own customized audio system, according to your vehicle and your desires. From the Focal discovery with the Universal range to the Utopia M excellence, listening in the car takes on a whole new dimension
Subwoofer
Choose one of Focal's subwoofers (passive, active, bass-reflex, ultra-flat...) and bring powerful, deep bass. Offering a variety of models in different formats, our range meets every installation need and is the ideal audio complement.
DSP & Amplifiers
To optimize the sound quality of your installation and enhance in-car listening, we offer a range of amplifiers and DSPs to match your loudspeakers. These Focal electronics let you experience the sensations of precise, controlled and stable sound.
Accessories & Cables
Discover Focal's range of amplifiers and cables for a complete solution. As a complement to your installation, amplifiers let you experience the sensations of precise, controlled sound, and cables answer questions linked to amplification and connections between components.
Focal Car Audio
Deliver exceptional sound clarity and precision for your vehicle
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Frequently Asked Questions
Q: Do I need an amplifier for this subwoofer?
A: Yes, unless it is an active (powered) subwoofer with a built-in amplifier. Passive subwoofers need an external amplifier matched to the RMS power and impedance shown in the Specification tab.
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: Does the Focal ISUB Active 2.1 need a separate amplifier?
A: No. It has its own built-in subwoofer amplifier (130W RMS, 260W max) plus a 2-channel amplifier rated at 2 x 55W RMS for the vehicle's front speakers.
Q: Will the ISUB Active 2.1 fit under my seat?
A: It measures 328 x 230 x 63 mm, so it slides under most seats, even tightly fitting ones. Check the available space under your seat before installation.
Q: How does the ISUB Active 2.1 connect to a factory radio?
A: It connects to the speaker (HP) outputs of the car radio using the ISO Plug and Play cable supplied by Focal. A wired remote bass controller is included for adjusting the bass level.
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