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In Phase Car Audio USW300 - 300W Underseat Compact SubwooferUSW300
£89.99 Save £110.00  was:£199.99
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Fit it Yourself?

Everything you need to fit it yourself at home

Only £30.00 

With Steering Wheel Control
Only £50.00 

5 Stars (24)

In Phase Car Audio USW300 - 300W Underseat Compact Subwoofer

£89.99 Save £110.00 (55%)  was:£199.99
5 Stars
24 Review(s) / write a review
Quickfind Code - 42186
Quick Summary:

Made from Diecast Aluminium fits snuggly under the seat of any car or in two seaters even behind the seats. Can be mounted inside the boot area also. Has complete control allowing for volume and phase adjustment by rotary hardwired.

Condition: New

Save £110.00 (55%)
rrp: £199.99
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Key Features

300W Underseat Compact Subwoofer - In Phase Car Audio USW300

The key thing about the In Phase USW 300 is the performance, the little active woofer really packs a punch, the bass response is amazing, you really do get SUB Bass from it. Its extremely responsive so the music has a completely different sound once added to the car. Many people think about changing speakers in you car, my advice is just add the USW 300 and you will think you have new life in your car! Enjoy its an awesome product.
This underseat subwoofer comes with it's own wiring. Please do not use any other kit. 

Download image of In Phase Car Audio USW300 Click here for Image of In Phase Car Audio USW300
Technical Specification
  • 5" x 8" Aluminium Speaker
  • 130w RMS
  • 300w Max Power
  • Die Cast Aluminium construction
  • Variable Subwoofer crossover 40-150hz
  • Speaker Frequency range 40-150hz
  • Bass Boost 26db Gain @ 42Hz
  • Bass Boost Frequency
  • Wired Remote Control
  • High Level speaker input
  • Line input
  • Max Power consumption 10Amp
  • LED Power Indicator
  • Super Compact design
  • W 280mm x H 200mm x D 75mm
  • Weight 3.7KG
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Customer reviews

A great little sub!
Nick Lewis on 04/05/2021 5 star rating

I bought this to replace a failing Vibe Optisound 8A and was looking at the pioneer underseat sub, but then stumbled upon this one. The good reviews and excellent price made me go for it. :-) I'm really impressed. It's half the size of the vibe (so now I have a sub that will actually fit under my seat) and sounds much better. The vibe also used to distort easily at louder volumes which the usw300 handles with ease. This is a fantastic little underseat subwoofer. Thanks, Car Audio Centre. Really quick delivery too. Very happy. :-)

Big Bass
Hayden on 28/04/2021 5 star rating

This is wicked, the bass is very loud and clear.

Very Impressed.
Gem Quinn on 26/04/2021 5 star rating

As a sound engineer/musician, I am fussy about sound. And as it is customary practice, I listen to mixes or masters in the van, on the way somewhere. I was getting tired of not hearing what was going on with the music, as my rear speakers were too far behind me, and my front ones were only really tweeters.. I drive a VW Transporter. I fitted this yesterday, and have covered a fair few miles since then.. I am absolutely thrilled at the amount of control, and quality on offer here. if you need a bass bath, its there, or if you need just to hear the music with all frequencies, it is as good as it will get in a space like that, Fitting was easy, with the supplied manual, and the head unit manual. Hardest part was routing the wires (All fitting wires thankfully included with this beauty). I ended up putting it in the passenger footwell, mounted on a piece of oak, slightly larger than the SW, and velcr-oing that to the floor rubber mat with Gorilla Glue. (careful now).. There are no vibrations, or odd things going on, and my remote is mounted on the dash, to the right of the Head unit, with some black foam double sided tape.. job definitely done, and out of sight, but definitely not out of mind. 10 stars.

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Questions/Answers About This Product
  • Question: 26 April 2021
    Hi, I have a VW T25 (1988)
    I'm want to put a Subwoofer in and am looking at this one.
    Does this come with wiring kit?


    Yes this unit comes with a wiring kit

    Found Useful? Yes 

  • Question: 24 April 2021
    Car: VW Transporter - 2005 >

    Will thus fit under the drivers seat in a T5? RCA fitment for a sub on the head unit is this the best option to give some good bass to kenwood door soeakers


    Yes, this will fit under the seat.

    Found Useful? Yes 

  • Question: 14 April 2021
    Car: Ford Fiesta - 2008>

    2014 Fiesta MK7.5 with OE Sony head unit. Which underseat sub is best USW300 or TS-WX130DA? Also how would these connect to the head unit? Is there an adaptor or splice only to speaker cables? Thanks


    The USW300 will be miles better. You can tap into the speaker cables or use a line out converter.

    Found Useful? Yes 

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Fitting Services

Need help with Installation?

Here at CarAudioCentre we offer a professional and reputable fitting service in all our stores. For all fitting enquiries and bookings please visit or call one of our nationwide stores. Our fitters can install your new car stereo, DAB radio, audio visual, speakers, subwoofers or amplifier. We can also help to connect your iPod or MP3 player to you existing audio unit and can offer the best advice on the right in-car entertainment for your vehicle, to further this more we also offer a total 100% custom installation service for demo and show vehicles. So if you have an idea come on in and run it past us, the possibilities are endless and we are never too busy for an enthusiastic chat about our favourite subject.

Please note:

"That our two year warranty on products is only applicable to purchases made directly from us and that have been fitted in one of our stores."

Our Stores:

542 546 Mansfield Road, Sherwood NG5 2FR
Tel: 0115 9624 986
743-745 Eastern Ave, Newbury Park, London, IG2 7RT
Tel: 0208 599 2368
835 Garratt Lane, Tooting, London, SW17 0PG
Tel: 0208 971 9181