– In Phase USW300 300W Underseat Subwoofer - Active Car Subwoofer with Built-in Amplifier

+ Great Sound, Great Quality, Easy to Install, Fantastic Value. - No RCA Leads. This is a great little sub if you’re after a fuller sound for your car. I installed a set of component speakers into a Kangoo van and was disappointed with the bass, so I fitted this and it’s made a massive difference! It’s a substantial well built item and has all the sound controls on the remote instead of fiddly dials on the back of the unit which makes it great to tune while it’s situ without messing around accessing it again. It comes with all the leads you need to get it running via high level input, but you will need to but a phono lead if you want to connect it via low level RCA.

I was a little sceptical before ordering and was considering building something to go under the floor in my SLK. However I purchased one to try and was not disappointed. I fitted under the floor in the passenger side footwell on an SLK, some models have an amp fitted there. At the same time I replaced the headunit with a powered android type with CarPlay. Fitting was easy as the Android head had cables to connect to and a sub output. The remote was remotes to the side of the centre console, convenient for adjustments should I need to. Build quality is good, sound quality is excellent for a compact sub of its size it compliments the rest of the speaker system. It was actually worth spending the money on this product, if you can’t get a big box in anywhere this is the ideal choice and with the remote just adds to the functionality, to be fair I’ve not had the need to alter it from the initial twiddling. I’ve written this after purchasing in August 2024, just in Dec 2025 now and still enjoying the sub!

For the price I can't complain. This does the job if you want to add a little low end and space is limited. It's not too difficult to install if you understand basic wiring. The sound quality isn't audiophile but it will improve any standard set up that lacks the low end. It has an adjustable crossover and gain controls on the unit itself, and an additional remote volume control. What's more it fits neatly under most car seats. You don't need to buy any additional equipment to get this going, all the wiring is also provided. Ok so maybe the bass isn't very tight, it's not going to compare to a 12 inch sub box booming insane levels of bass in your boot but it's an underseat space saving 6" woofer with a built-in amp (active) for less than £150, it is a massive improvement to standard car speakers. Personally I dial the crossover from my head unit (car stereo) as it has a sub out, this will give better results but you can use your factory stereo and wire in using the speaker connections on the back. It's never going to compete with a proper sub but it's nice and compact and provides the extra bass I was missing without breaking the bank. Edit: I've been using this unit for a while now and no complaints. I actually take the longer way home so I can enjoy the music 🎶

What an incredible bit of kit! I’ve installed it under the drivers seat of my 2009 Smart Fortwo (wont fit under the passenger seat). It has transformed the sound quality in the car. Being a small car it only has two speakers, i upgraded these to some decent three ways but it still lacked some depth. This has sorted that out. I installed it using the High power input (speaker feed). It’ll take some fettling to get things sounding perfect but thats a personal preference. I would 100% recommend this. Not sure how effective it would be in a much bigger car but definitely does what it should do.

This sub is incredibly solidly built, the case being die-cast aluminium. It easily slipped under the passenger seat of my son’s Aygo (mk1), and held in place ok with some Velcro pads (not supplied) rather than trying to screw it down. The kit is complete with cables for many different types of installation and the instructions are very clear. We did have one installation issue that arose because we also changed out the Argo’s old CD player head unit for a more modern Pioneer one with bluetooth hands-free; The adapter that came with the radio had to have its yellow (permanent 12v) and red (switched 12v) cables crossed over as the subwoofer was not powering up correctly (and yes, the blue/white remote device wire was correctly installed!). After this, it was plain sailing to hide the wires under the central console without having to remove any seats for access. The result is a stereo with MUCH better bass that’s audible at even motorway cruising speeds. A very simple and very useful upgrade to the Aygo.

Fantastic bit of kit for the price,solid in build and design and very simple to fit with clear instructions. Hardest part was tracing the live feed wire from battery to unit. Sound is amazing at all levels with easily adjustable settings. Fits neatly under the seat. Love it

There's a lot of debate about how best to spend your ££s on improving the gutless, tinny sound of a factory car stereo, especially in small cars that are a few years old. Some would say replace the head unit first, others argue you should start with upgrading the door speakers or put in an amp. My advice is install this underseat sub before you do any other upgrades...and it'll really surprise you just how big the impact is on the sound! I installed it in a 2014 Toyota Aygo, fits perfectly under the drivers seat. It totally transformed the sound in the car and even drops pretty low on drum n bass, which was remarkable considering its tiny size and low price. It also means you can turn down the bass on the factory head unit and crank the standard speakers louder without melting, which overall gives a pretty good impression of having a decent sound system in your motor. It's a bit of a faff to install, running cables etc, but that would be the case with any car audio gear. If you don't know your way around car electrics, pay to have it done properly. This sub is a really low cost way of making your weezing old stereo a whole lot more fun to listen to.

This unit feels robust and very well made. Easy to install under the seat of my Mercedes 190e. The sound is great, I love my music with plenty of bass. It wont shatter the glass but is plenty powerful enough for my needs. My only negative comment is the remote, it looks and feels cheap as if the designer of the unit ran out of ideas for the remote, thin cheap plastic.