---
product_id: 698387382
title: "In Phase USW300 Underseat Subwoofer | Car Subwoofer with Built in Amplifier | 300W Active Subwoofer Car | Compact Design Under Seat Subwoofer Car | Heavy Duty Durable Construction | Designed in the UK"
brand: "in phase"
price: "1304.77 DT"
currency: TND
in_stock: true
category: "In Phase"
url: https://www.desertcart.tn/products/698387382-in-phase-usw300-underseat-subwoofer-car-subwoofer-with-built-in
store_origin: TN
region: Tunisia
---

# Compact 16cm width fits anywhere 300W max power output Die-cast aluminum chassis In Phase USW300 Underseat Subwoofer | Car Subwoofer with Built in Amplifier | 300W Active Subwoofer Car | Compact Design Under Seat Subwoofer Car | Heavy Duty Durable Construction | Designed in the UK

**Brand:** in phase
**Price:** 1304.77 DT
**Availability:** ✅ In Stock

## Summary

> 🎶 Feel the bass, not the bulk — power your ride with precision!

## Quick Answers

- **What is this?** In Phase USW300 Underseat Subwoofer | Car Subwoofer with Built in Amplifier | 300W Active Subwoofer Car | Compact Design Under Seat Subwoofer Car | Heavy Duty Durable Construction | Designed in the UK by in phase
- **How much does it cost?** 1304.77 DT with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.tn](https://www.desertcart.tn/products/698387382-in-phase-usw300-underseat-subwoofer-car-subwoofer-with-built-in)

## Best For

- in phase enthusiasts

## Why This Product

- Trusted in phase brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Trusted UK Audio Expertise:** Backed by 500+ years of combined R&D experience from In Phase, a leader in premium car audio innovation.
- • **Power-Packed Bass Performance:** 300W max output with 150W RMS delivers deep, punchy sub-bass that transforms your drive.
- • **Built to Last, Built to Perform:** Heavy-duty die-cast aluminum chassis prevents flex and maximizes bass output under full power.
- • **Rattle-Free Aluminium Cone Tech:** Lightweight yet robust aluminium cone with damping materials ensures crystal-clear, distortion-free bass.
- • **Discreet Installation, Maximum Impact:** Slim 5x16x5 cm design fits seamlessly under seats or in tight spaces without sacrificing sound quality.

## Overview

The In Phase USW300 is a compact underseat car subwoofer featuring a built-in 300W amplifier and a robust aluminium cone for deep, distortion-free bass. Its die-cast aluminum chassis ensures durability and no flexing under power, while its slim profile allows versatile installation in tight vehicle spaces. Designed by a UK brand with over 500 years of combined audio R&D, it delivers premium sub-bass performance that elevates your in-car audio experience.

## Description

Free delivery and returns on eligible orders. Buy In Phase USW300 Underseat Subwoofer | Car Subwoofer with Built in Amplifier | 300W Active Subwoofer Car | Compact Design Under Seat Subwoofer Car | Heavy Duty Durable Construction | Designed in the UK at desertcart UK.

## Features

- Subwoofer for Car - With a built in amplifier, max output of 300 W and 150 W RMS, the In Phase USW300 is a true pocket powerhouse of audio performance.
- Coned Aluminium Active Subwoofer Car - Aluminium Cones are light in weight and can be really stiff, but they are really robust cones that rarely go wrong. This sub has a damping material built into its cone and spider to ensure a rattle-free performance and deep bass
- Heavy duty durable construction - Die Cast Aluminium Chassis - no plastic structure here. The metal body is part of a secure and rigid structure, no flexing body when the unit is in full power, this also helps with bass output.
- Compact and discrete - Allowing to install the USW300 anywhere within vehicles boot, under seats, behind seats or in the foot well
- Trusted Brand - In Phase is a UK based brand, our team currently has over 500 years of audio research and development experience, creating quality products from premium material that our customer deserve, including, car audio speakers & subwoofers.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B089GZ6F14 |
| Age Range Description | Adult |
| Antenna Location | Car |
| Audio Driver Size | 8 Inches |
| Audio Driver Type | Dynamic Driver |
| Audio Output Mode | Stereo |
| Best Sellers Rank | 4,198 in Electronics & Photo ( See Top 100 in Electronics & Photo ) 1 in Car Enclosed Subwoofer Systems |
| Box Contents | Car Subwoofer Active Enclosure, Wiring Kit, Mounting Brackets, Remote Controller, Instruction Manual |
| Brand Name | In Phase |
| Colour | USW300 |
| Compatible Devices | Car |
| Compatible with Vehicle Type | Car |
| Connectivity Protocol | Auxiliary |
| Control Method | Remote |
| Controller Type | Remote Control |
| Country of Origin | China |
| Customer Package Type | Standard packaging |
| Customer Reviews | 4.4 4.4 out of 5 stars (437) |
| EU Spare Part Availability Duration | 2 Years |
| Enclosure Material | Aluminum/Die Cast Aluminum |
| Frequency Response | 150 Hz |
| Global Trade Identification Number | 05060047672757 |
| Input Voltage | 12 Volts |
| Is Waterproof | false |
| Item Dimensions D x W x H | 5D x 16W x 5H centimetres |
| Item Type Name | Underseat Active Subwoofer |
| Item Weight | 1.5 Kilograms |
| MP3 player | No |
| Manufacturer | In Phase |
| Maximum Speaker Output Power (in watts) | 300 Watts |
| Model Name | USW300 |
| Model Number | USW300 |
| Mounting Type | Underseat Mount |
| Network Connectivity Technology | Auxiliary |
| Number of Audio Channels | 2.0 |
| Number of Items | 1 |
| Power Source | Corded Electric |
| Product Features | Built-in Amplifier, Aluminium Coned Subwoofer |
| Product Warranty | 5 year |
| Speaker Size | 28 Centimetres |
| Speaker Type | Subwoofer |
| Specific Uses For Product | Car |
| Subwoofer Connectivity Technology | Wired |
| Tweeter Diameter | 1 Inches |
| Warranty Type | Limited |
| Wireless Technology Type | No Wireless Communication Technology |
| Woofer Driver Diameter | 200 Millimetres |

## Product Details

- **Audio output mode:** Stereo
- **Brand:** In Phase
- **Connectivity technology:** Auxiliary
- **Frequency response:** 150 Hz
- **Input voltage:** 12 Volts
- **Material:** Aluminum/Die Cast Aluminum
- **Model name:** USW300
- **Mounting type:** Underseat Mount
- **Speaker maximum output power:** 300 Watts
- **Speaker type:** Subwoofer

## Images

![In Phase USW300 Underseat Subwoofer | Car Subwoofer with Built in Amplifier | 300W Active Subwoofer Car | Compact Design Under Seat Subwoofer Car | Heavy Duty Durable Construction | Designed in the UK - Image 1](https://m.media-amazon.com/images/I/81u+V61e6lL.jpg)

## Available Options

This product comes in different **Style** options.

## Questions & Answers

**Q: Does this require two connections? One rca from the unit to the sub out connection on headunit. And one to battery?**
A: Yes, it needs 12v power, you need the audio connection from the head unit ( RCA/sub out ) permanent live to the battery and earth to the chassis or battery, then the remote wire to the head unit which tells the sub to turn on and off, all aftermarket head units have a remote live connection for this purpose 👍

**Q: Can i use it in my home system? I have a musical fidelity amp and Linn speakers**
A: Yes, however you would need a 12V transformer with 20amps current supply.

**Q: how do you turn off if connected straight to battery?**
A: It detects the audio signal and turns itself on and off when you turn your head unit on/off. It's clever like that :-)

**Q: Can I wire to cigarette lighter for power? Says max 120w**
A: You cannot. You need to wire the active subwoofer directly for power to the battery Positive. If you are unsure how to do this, many videos on Youtube. It also explains in the instructions. However we always recommend professional installation if you are not sure.

## Frequently Bought Together

- In Phase USW300 300W Underseat Subwoofer - Active Car Subwoofer with Built-in Amplifier
- In Phase XTC17.2 250W 2 x 6.5 Inch Car Speakers - 17cm Car Speaker for Door or Parcel Shelf - Audio Speakers & Subwoofers

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*Product available on Desertcart Tunisia*
*Store origin: TN*
*Last updated: 2026-08-28*