UK car audio comparison

Best Underseat Bass Upgrades
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

Pioneer TS-WX010A Ultra Compact Space Saving Active Subwoofer with built-in Class-D Amplifier (160 W)

A active 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	Warranty	Product Type	Subwoofer Design	Size	Listed Power	Type	Feature	Shipping Weight	Full specifications
Pioneer TS-WX010A Ultra Compact Space Saving Active Subwoofer with built-in Class-D Amplifier (160 W)	£116.19	In stock	Pioneer	TS-WX010A	Not listed	Pioneer	Active	Not listed	160W	OEM Headunit Connection, Under Seat, Underseat Subwoofer	Built In Amplifier	1 kg	Class: D amplifier
Pioneer TS-WX140DA 170W 20cm Underseat Subwoofer	£141.78	In stock	Pioneer	TS-WX140DA	Not listed	Underseat Car Subwoofers	Active	Not listed	170W	Not listed	Not listed	5 kg	Class: D amplified subwoofers integrating DIGITAL BASS CONTROL, D technology, Pioneer’s TS-WX140DA is even easier to install, as it is capable of taking both High (
Focal ISUBBMW-4 Underseat 4 Ohm Subwoofer upgrade for BMW Vehicles	£199.00	In stock	Focal	ISUB BMW-4	Not listed	Underseat Car Subwoofers	Active	Not listed	Not listed	speakerupgrade	Not listed	Not listed	Power Detail: 4 Ohm Size Detail: 10 inch
In Phase USW12 Dual underseat active subwoofer system 600 watts with bass and phase wired remote control	£199.99	In stock	In Phase	USW12	2 Year Warranty	Underseat Car Subwoofers	Active	12 inch	600W	OEM Headunit Connection, Under Seat, Underseat Subwoofer	Built In Amplifier, Dual Voice Coil	5 kg	Power Detail: 2 Ohm
BLAM RELAX BL-MSP25P MSP 25P Extra-Slim Passive Underseat Car Subwoofer	£260.00	In stock	BLAM	BL-MSP25P	Not listed	Underseat Car Subwoofers	Passive	Not listed	Not listed	Not listed	Not listed	Not listed	All listed fields are shown

Product notes

What each pick is best at

Best overall bass upgrade

Pioneer TS-WX010A Ultra Compact Space Saving Active Subwoofer with built-in Class-D Amplifier (160 W)

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

What we like

Lowest listed price in this comparison at £116.19, £25.59 below Pioneer TS-WX140DA.
The only pick here listing 160W power, giving it a clear difference from the other 4 options.
Its active design includes amplification in the product, unlike passive options that need a separate amp.

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	£116.19
Availability	In stock
Listed Power	160W
Model	TS-WX010A
Subwoofer Design	Active
Brand	Pioneer
Class	D amplifier
Feature	Built In Amplifier
Product Type	Pioneer
Shipping Weight	1 kg
Type	OEM Headunit Connection, Under Seat, Underseat Subwoofer

Check CarAudioCentre.co.uk

Best for compact installations

Pioneer TS-WX140DA 170W 20cm Underseat Subwoofer

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

What we like

At £141.78, it costs £25.59 more than Pioneer TS-WX010A, so the extra spend is tied to the specification and fitment choice.
The only pick here listing 170W power, giving it a clear difference from the other 4 options.
Its active design includes amplification in the product, unlike passive options that need a separate amp.

What we don't like

It is £25.59 above the cheapest pick, so the higher price depends on whether the distinct 170W power suits the installation.
The enclosure and underseat or boot dimensions still need checking, even where the product is described as compact.

Price	£141.78
Availability	In stock
Listed Power	170W
Model	TS-WX140DA
Subwoofer Design	Active
Brand	Pioneer
Class	D amplified subwoofers integrating DIGITAL BASS CONTROL, D technology, Pioneer’s TS-WX140DA is even easier to install, as it is capable of taking both High (
Product Type	Underseat Car Subwoofers
Shipping Weight	5 kg

Check CarAudioCentre.co.uk

Best for boot-based systems

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 £82.81 more than Pioneer TS-WX010A, so the extra spend is tied to the specification and fitment choice.
Its listed Active design matches 3 other picks, 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 £82.81 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 factory stereos

In Phase USW12 Dual underseat active subwoofer system 600 watts with bass and phase wired remote control

A 12-inch active subwoofer choice for adding more weight to the system.

What we like

At £199.99, it costs £83.80 more than Pioneer TS-WX010A, so the extra spend is tied to the specification and fitment choice.
The only pick here listing 12-inch size, giving it a clear difference from the other 4 options.
Its active design includes amplification in the product, unlike passive options that need a separate amp.

What we don't like

It is £83.80 above the cheapest pick, so the higher price depends on whether the distinct 12-inch size suits the installation.
The enclosure and underseat or boot dimensions still need checking, even where the product is described as compact.

Price	£199.99
Availability	In stock
Listed Power	600W
Model	USW12
Size	12 inch
Subwoofer Design	Active
Warranty	2 Year Warranty
Brand	In Phase
Feature	Built In Amplifier, Dual Voice Coil
Power Detail	2 Ohm
Product Type	Underseat Car Subwoofers
Shipping Weight	5 kg
Type	OEM Headunit Connection, Under Seat, Underseat Subwoofer

Check CarAudioCentre.co.uk

Best for stronger low end

BLAM RELAX BL-MSP25P MSP 25P Extra-Slim Passive Underseat Car Subwoofer

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

What we like

At £260.00, it costs £143.81 more than Pioneer TS-WX010A, so the extra spend is tied to the specification and fitment choice.
The only pick here listing Passive design, giving it a clear difference from the other 4 options.
The passive design leaves amplifier choice open for buyers already planning a separate bass channel.

What we don't like

It is £143.81 above the cheapest pick, so the higher price depends on whether the distinct Passive design suits the installation.
A separate amplifier and suitable wiring are required, unlike the active alternatives.

Price	£260.00
Availability	In stock
Model	BL-MSP25P
Subwoofer Design	Passive
Brand	BLAM
Product Type	Underseat 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 Underseat Bass Upgradesin 2026.

Pioneer TS-WX010A Ultra Compact Space Saving Active Subwoofer with built-in Class-D Amplifier (160 W)

Our picks compared

What each pick is best at

Pioneer TS-WX010A Ultra Compact Space Saving Active Subwoofer with built-in Class-D Amplifier (160 W)

What we like

What we don't like

Pioneer TS-WX140DA 170W 20cm Underseat 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

In Phase USW12 Dual underseat active subwoofer system 600 watts with bass and phase wired remote control

What we like

What we don't like

BLAM RELAX BL-MSP25P MSP 25P Extra-Slim Passive Underseat Car Subwoofer

What we like

What we don't like

What to check before ordering

Best Underseat Bass Upgrades
in 2026.