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In Phase Car Audio USW300 - 300W Underseat Compact SubwooferUSW300
£99.99 Save £50.00  was:£149.99
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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 (18)

In Phase Car Audio USW300 - 300W Underseat Compact Subwoofer

£99.99 Save £50.00 (33%)  was:£149.99
5 Stars
18 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 £50.00 (33%)
rrp: £149.99
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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

Ron on 04/02/2021 5 star rating

Put two of these in my LR Defender. Along with some Focal 4", I have sound deadened the vehicle as well. This sub is amazing. I can feel every rhythm in the music I play

Inphase underseat subwoofer USW300
ROBERT on 03/02/2021 5 star rating

Very surprised for such a small unit on power it has.i had to get rid of my big sub due to needing the space in my boot. So very pleased that this doesn't take up space.

Ronald Peters on 02/02/2021 5 star rating

Wow, this Underseat sub works amazing, perfect size for anywhere in the car! even behind seats in a Ferrari 458. definitely recommended for sound and quality!

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Questions/Answers About This Product
  • Question: 28 February 2021
    Hi. Does this sub require a power supply from the car battery. I have a supply to my current mono block amp including RCA but as I need the boot space can the mono block supply connect to this


    This underseat sub will require a 12V power feed regardless of the current system fitted.

    Found Useful? Yes 

  • Question: 24 January 2021
    Car: Honda Jazz - 2008>

    1) if fitting from stock head unit does it take one of the outputs out (like rear speakers) to work.
    2) there is another in phase which seems to be similar usw 10.which is better?


    The USW10 is better but for the price, the USW300 is better value for money.

    Yes, I would use a line out converter for better performance. See below

    In Phase Speaker to Rca Converter adjustable output gain

    Found Useful? Yes 

  • Question: 29 November 2020
    Car: Seat Leon - 2007>

    I have a 2018 seat leon, was about to purchase this sub. Just wondering if there is any additional wiring I will require to connect this to a standard stereo. Many thanks


    The USW300 will come with all the cables required for installation.

    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