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Smart Car Audio and Speaker Upgrades UK

Upgrade the sound in your Fortwo Coupe, Cabrio or EQ with Smart car audio from Bass Junkies. The range centres on Focal vehicle-specific 6.5 inch coaxial speakers built for the 2014 to 2021 Smart door location, supplied with the correct connector so there is no cutting, no adapter rings and no wiring changes. Each 240 watt pair delivers a clear, punchy sound that fills the compact Smart cabin without an amplifier. Stereos, fitting kits and subwoofers are available too.

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Smart car audio and speaker upgrades in 2026

The Smart Fortwo is one of the cleverest city cars on UK roads, but the factory speakers were never a priority. The standard door drivers are small, lightly built units that sound thin at low volume and harsh once you turn it up to beat road noise. The cabin is compact, so a modest upgrade makes a bigger difference than it would in a large saloon. The 2014 to 2021 Fortwo and Forfour share a platform and door design with the Renault Twingo, which means proven plug and play speaker kits are available. This guide explains what we stock, which Smart models it suits and how to get it fitted.

Popular Smart models we stock for

Fortwo Coupe (2014 to 2021). The third generation two seater uses a standard 6.5 inch front door speaker location, so the Focal kit drops straight in.
Fortwo Cabrio (2014 to 2021). The convertible shares the same door fitment, and the extra road noise with the roof folded makes a stronger speaker even more worthwhile.
Fortwo EV and EQ Fortwo (2014 to 2021). The electric version is near silent on the move, which exposes weak factory speakers. A quality coaxial pair makes the most of that quiet cabin.
Forfour (2014 to 2021). The four door model uses the same front door location, so the upgrade path is identical.

Brand quality at a glance

Focal. French engineered speakers made specifically for the Smart door location and connector, so fitting is plug and play with no drilling or soldering.
Pioneer. The leading name in double DIN stereos with Apple CarPlay and Android Auto for Smart owners who want a modern screen.
Kenwood. Wired and wireless CarPlay head units with strong preamp outputs for adding an amplifier later.
Alpine. Premium stereos and compact amplifiers for owners who want the best sound quality in a small cabin.

Why a coaxial kit suits the Smart

The Focal kit is a 240 watt 2 way coaxial design: a 6.5 inch woofer with the tweeter mounted in the centre of the cone. In a two seater the driver sits close to the door speakers, so a coaxial pair delivers clear vocals and detail without needing separate tweeter mounts or extra wiring. The stiff cone and larger magnet give far more midbass than the factory units, which is exactly what the Fortwo lacks. Sensitivity is high enough to run from the factory or an aftermarket head unit, and the kit scales up if you add a small amplifier later.

Compatibility and fitting

The speaker kits fit without adapters. If you are also replacing the head unit in a Smart you will need:

Fascia adapter. Reshapes the Smart dash aperture to take a double DIN stereo with a factory finish.
ISO harness. Plugs into the original connector so no factory wiring is cut.
Steering-wheel control adapter. Keeps the volume and track buttons on the wheel working with the new stereo.
Aerial adapter. Converts the Fakra aerial plug to the DIN socket used by aftermarket stereos and keeps DAB and FM reception strong.

Smart is part of the Mercedes family, so our wider Mercedes car audio range and the Smart fitting parts page cover stereos, cameras and adapters for most models.

Adding bass to a Smart

Boot space in a Fortwo is limited, so a slimline active subwoofer that sits under a seat or against the rear bulkhead is the sensible route and keeps the luggage area usable. The Forfour has room for a compact enclosure behind the rear seats if you want deeper output. Pairing a small subwoofer with the Focal coaxial kit gives a full range system that the factory setup cannot match, and in a cabin this size it takes very little power to feel it.

Common Smart fitting issues we solve

Later Smarts with the factory Media System touchscreen integrate phone, navigation and vehicle settings, so a full stereo swap is not always practical. In these cars the speaker kit is the best value upgrade because it improves every source without touching the screen. Cars with the basic radio convert easily to a CarPlay head unit with the correct fascia and harness, which we supply with every stereo order.

Fitting in Wolverhampton or delivery UK wide

Order online for fast UK delivery, or book a fitting slot at our workshop and have speakers, stereo or subwoofer installed while you wait. Our fitters work on small cars every week and know the Smart door cards and trim clips well, so the job is done cleanly with no rattles.

Why buy from Bass Junkies

Bass Junkies has supplied and fitted car audio upgrades since 1995. Every order ships from our Wolverhampton workshop, where the same team that fits systems for local customers picks and checks your parts. If you are unsure which kit suits your Smart, call 01902 863 005 and we will confirm the fit before you order.