UK car audio comparison

Best Focal Car Subwoofers
in 2026.

A practical comparison of car subwoofers using enclosure type, power, dimensions and the installation space they need.

Prices and stock should be checked on the retailer page before purchase.

Our approach. We compare the specifications shown on the retailer product pages and explain who each model suits. This is not a hands-on test.

Our pick

Focal SUB10 10" Subwoofer

A 10-inch bass subwoofer choice for adding more weight to the system.

Check price

Full specifications

Our picks compared

This table includes every verified specification available for the products in this roundup. Check the retailer page for the latest price, stock and fitment details.

Product	Price	Availability	Brand	Model	Product Type	Subwoofer Design	Size	Listed Power	Rms Power	Type	Full specifications
Focal SUB10 10" Subwoofer	£109.99	In stock	Focal	SUB10	Car Subwoofers	Not listed	10 inch	Not listed	Not listed	Not listed	All listed fields are shown
Focal SUB10DUAL 10" Dual Voice Coil Subwoofer	£129.99	In stock	Focal	SUB10DUAL	Car Subwoofers	Not listed	10 inch	Not listed	Not listed	Not listed	All listed fields are shown
Focal Slatefiber SUB20SF 200mm Car Subwoofer	£179.99	In stock	Focal	SUB20SF	Car Subwoofers	Not listed	Not listed	Not listed	Not listed	Not listed	All listed fields are shown
Focal ISUBBMW-4 Underseat 4 Ohm Subwoofer upgrade for BMW Vehicles	£199.00	In stock	Focal	ISUB BMW-4	Underseat Car Subwoofers	Active	Not listed	Not listed	Not listed	speakerupgrade	Power Detail: 4 Ohm Size Detail: 10 inch
Focal ISUBACTIVE2.1 8" Compact Subwoofer with Built-in 2.1 Amplification	£429.99	In stock	Focal	ISUBACTIVE2.1	Subwoofer	Active	8 inch	260W	Not listed	Underseat Subwoofer	All listed fields are shown
Focal SUB-5KM-K2M 5KM 145mm Sub	£429.99	In stock	Focal	SUB-5KM-K2M	Car Subwoofers	Not listed	Not listed	400W	200W	Not listed	Impedance: 4 Ω Nominal power : 200 W RMS Sensitivity : 86 dB Surround material : Butyl

Product notes

What each pick is best at

Best overall bass upgrade

Focal SUB10 10" Subwoofer

A 10-inch bass subwoofer choice for adding more weight to the system.

What we like

Lowest listed price in this comparison at £109.99, £20.00 below Focal SUB10DUAL.
Its listed 10-inch size matches 1 other pick, making like-for-like installation planning easier.
The product type gives a clear starting point for deciding between a compact bass upgrade and a separate amplifier setup.

What we don't like

Unlike some alternatives, the listing does not show a comparable design figure, so matching it to the rest of the system takes more checking.
The enclosure and underseat or boot dimensions still need checking, even where the product is described as compact.

Price	£109.99
Availability	In stock
Model	SUB10
Size	10 inch
Brand	Focal
Product Type	Car Subwoofers

Check CarAudioCentre.co.uk

Best for compact installations

Focal SUB10DUAL 10" Dual Voice Coil Subwoofer

A 10-inch bass subwoofer choice for adding more weight to the system.

What we like

At £129.99, it costs £20.00 more than Focal SUB10, so the extra spend is tied to the specification and fitment choice.
Its listed 10-inch size matches 1 other pick, making like-for-like installation planning easier.
The product type gives a clear starting point for deciding between a compact bass upgrade and a separate amplifier setup.

What we don't like

It is £20.00 above the cheapest pick without a clearly unique listed specification to explain the difference.
The enclosure and underseat or boot dimensions still need checking, even where the product is described as compact.

Price	£129.99
Availability	In stock
Model	SUB10DUAL
Size	10 inch
Brand	Focal
Product Type	Car Subwoofers

Check CarAudioCentre.co.uk

Best for boot-based systems

Focal Slatefiber SUB20SF 200mm Car Subwoofer

A bass subwoofer choice for adding more weight to the system.

What we like

At £179.99, it costs £70.00 more than Focal SUB10, so the extra spend is tied to the specification and fitment choice.
The model and product category are clearly identified for checking against the vehicle and wider system.
The product type gives a clear starting point for deciding between a compact bass upgrade and a separate amplifier setup.

What we don't like

It is £70.00 above the cheapest pick without a clearly unique listed specification to explain the difference.
The enclosure and underseat or boot dimensions still need checking, even where the product is described as compact.

Price	£179.99
Availability	In stock
Model	SUB20SF
Brand	Focal
Product Type	Car Subwoofers

Check CarAudioCentre.co.uk

Best for factory stereos

Focal ISUBBMW-4 Underseat 4 Ohm Subwoofer upgrade for BMW Vehicles

A active subwoofer choice for adding more weight to the system.

What we like

At £199.00, it costs £89.01 more than Focal SUB10, so the extra spend is tied to the specification and fitment choice.
Its listed Active design matches 1 other pick, making like-for-like installation planning easier.
Its active design includes amplification in the product, unlike passive options that need a separate amp.

What we don't like

It is £89.01 above the cheapest pick without a clearly unique listed specification to explain the difference.
The enclosure and underseat or boot dimensions still need checking, even where the product is described as compact.

Price	£199.00
Availability	In stock
Model	ISUB BMW-4
Subwoofer Design	Active
Brand	Focal
Power Detail	4 Ohm
Product Type	Underseat Car Subwoofers
Size Detail	10 inch
Type	speakerupgrade

Check CarAudioCentre.co.uk

Best for stronger low end

Focal ISUBACTIVE2.1 8" Compact Subwoofer with Built-in 2.1 Amplification

A 8-inch active subwoofer choice for adding more weight to the system.

What we like

At £429.99, it costs £320.00 more than Focal SUB10, so the extra spend is tied to the specification and fitment choice.
The only pick here listing 8-inch size, giving it a clear difference from the other 5 options.
Its active design includes amplification in the product, unlike passive options that need a separate amp.

What we don't like

It is £320.00 above the cheapest pick, so the higher price depends on whether the distinct 8-inch size suits the installation.
The enclosure and underseat or boot dimensions still need checking, even where the product is described as compact.

Price	£429.99
Availability	In stock
Listed Power	260W
Model	ISUBACTIVE2.1
Size	8 inch
Subwoofer Design	Active
Brand	Focal
Product Type	Subwoofer
Type	Underseat Subwoofer

Check CarAudioCentre.co.uk

Best for flexible installation

Focal SUB-5KM-K2M 5KM 145mm Sub

A bass subwoofer choice for adding more weight to the system.

What we like

At £429.99, it costs £320.00 more than Focal SUB10, so the extra spend is tied to the specification and fitment choice.
The only pick here listing 400W power, giving it a clear difference from the other 5 options.
The product type gives a clear starting point for deciding between a compact bass upgrade and a separate amplifier setup.

What we don't like

It is £320.00 above the cheapest pick, so the higher price depends on whether the distinct 400W power suits the installation.
The enclosure and underseat or boot dimensions still need checking, even where the product is described as compact.

Price	£429.99
Availability	In stock
Listed Power	400W
Model	SUB-5KM-K2M
Rms Power	200W
Brand	Focal
Impedance	4 Ω Nominal power : 200 W RMS Sensitivity : 86 dB Surround material : Butyl
Product Type	Car Subwoofers

Check CarAudioCentre.co.uk

Buying guide

What to check before ordering

Start with the space available, then compare RMS power, enclosure type and input options. A factory stereo may need high-level inputs or a line-out converter, while a passive subwoofer needs a separate amplifier.

Use the model number as the final reference. Retailer images and prices can change, and vehicle fitment should be confirmed for the exact make, model and year.

Best Focal Car Subwoofersin 2026.

Focal SUB10 10" Subwoofer

Our picks compared

What each pick is best at

Focal SUB10 10" Subwoofer

What we like

What we don't like

Focal SUB10DUAL 10" Dual Voice Coil Subwoofer

What we like

What we don't like

Focal Slatefiber SUB20SF 200mm Car Subwoofer

What we like

What we don't like

Focal ISUBBMW-4 Underseat 4 Ohm Subwoofer upgrade for BMW Vehicles

What we like

What we don't like

Focal ISUBACTIVE2.1 8" Compact Subwoofer with Built-in 2.1 Amplification

What we like

What we don't like

Focal SUB-5KM-K2M 5KM 145mm Sub

What we like

What we don't like

What to check before ordering

Best Focal Car Subwoofers
in 2026.