---
product_id: 436348969
title: "Car Audio XTB-828R 8\" 400W Active Subwoofer with Passive Radiator and Class D Amplifer , Black"
brand: "in phase"
price: "$996.46"
currency: USD
in_stock: true
reviews_count: 13
category: "In Phase"
url: https://www.desertcart.ec/products/436348969-car-audio-xtb-828r-8-400w-active-subwoofer-with-passive
store_origin: EC
region: Ecuador
---

# 8" Glass Fibre Subwoofer Cone Compact 16W x 5D x 5H cm footprint 400W Class D Amplifier Car Audio XTB-828R 8" 400W Active Subwoofer with Passive Radiator and Class D Amplifer , Black

**Brand:** in phase
**Price:** $996.46
**Availability:** ✅ In Stock

## Summary

> 🚗💥 Compact Bass, Massive Impact – Own the Road’s Soundtrack!

## Quick Answers

- **What is this?** Car Audio XTB-828R 8" 400W Active Subwoofer with Passive Radiator and Class D Amplifer , Black by in phase
- **How much does it cost?** $996.46 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.ec](https://www.desertcart.ec/products/436348969-car-audio-xtb-828r-8-400w-active-subwoofer-with-passive)

## 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

- • **Durable Glass Fibre Cone:** Lightweight yet rigid for crystal-clear sound and long-lasting performance.
- • **Space-Savvy Compact Design:** Fits snugly in tight car boots or small interiors—premium bass without the bulk.
- • **Passive Radiator Technology:** Enhances low-frequency response for richer, punchier bass without extra power draw.
- • **Powerful 400W Class D Amplifier:** Delivers deep, distortion-free bass that commands attention without draining your battery.
- • **Plug & Play with Included Cables:** Hassle-free installation with remote bass gain control to fine-tune your perfect thump.

## Overview

The In Phase Car Audio XTB-828R is a sleek 8-inch active subwoofer featuring a 400W Class D amplifier and a passive radiator for enhanced bass depth. Its compact design (16W x 5D x 5H cm) fits perfectly in small car spaces without sacrificing sound quality. Equipped with a durable glass fibre cone and all necessary cables, it offers easy installation and powerful, distortion-free bass tailored for small to mid-sized vehicles.

## Description

In Phase Car Audio XTB-828R 8" 400W Active Subwoofer with Passive Radiator and Class D Amplifer , Black : desertcart.co.uk: Electronics & Photo

Review: Boomy compact subwoofer. - Was looking to add bass to my little Suzuki Alto. As you can imagine the original two 4inch paper speakers were inadequate, so added a pair of Vibe 4inch 2way components and a pair of 6x9 which dramatically improved sound quality. However deep bass was missing and since space was a premium was looking for a compact subwoofer. The In-phase XTB828R certainly provides decent bass for the size and price. Considering it's an 8inch sub with a passive sound radiator, and comes with all the necessary wiring, you can't go wrong. One thing to note when I first installed it, the bass seemed underwhelming i.e. not loud. But adjusting the output gain from my head unit sorted that out (Not the same as volume!). Overall a decent sub to add some bass. Wont shake any windows but hey I think it works best in a small car. If you you have a normal sized car you would need a 12inch sub ;)
Review: Excellent Sub! - I have been using this now for almost a year, anyone saying this sub is underwhelming just have not configured it right as this thing can really rumble, the auto on feature is the reason i got this one due to not being able to access the necessary cables due to array of other devices the vehicle already has onboard but with the right amp and crossover this sounds incredible and I would highly recommend.

## Features

- PASSIVE RADIATOR: a speaker with no voice coil or magnet, basically a speaker cone. This is not connected to the amp at all
- COMPACT DESIGN: This sub is only the size of a small desktop computer case. This small footprint allows the user to add thumping bass without compromising space in the boot
- SUPERIOR SUBWOOFER CONE: The glass fibre subwoofer cone is purpose built for this package, it is lightweight, durable and rigid without compromising sound quality
- Power Source Type: Corded Electric

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B09ZPMVHCV |
| Best Sellers Rank | 65,257 in Electronics & Photo ( See Top 100 in Electronics & Photo ) 30 in Car Enclosed Subwoofer Systems |
| Colour | Black |
| Compatible devices | Personal Computer |
| Control method | Voice |
| Customer Reviews | 4.0 4.0 out of 5 stars (38) |
| Date First Available | 6 May 2022 |
| Included components | All Cables Included, Remote Bass Gain |
| Is waterproof | False |
| Item Weight | 7.82 kg |
| Item model number | XTB-828R |
| Manufacturer | In Phase |
| Manufacturer part number | XTB-828R |
| Number of items | 1 |
| Power source | Corded Electric |
| Product dimensions | 5D x 16W x 5H centimetres |
| Speaker size | 8 Inches |
| Special Features | Passive Radiator |
| Surround-sound channel configuration | 2.0 |
| Warranty type | Limited |
| Wattage | 400 watts |
| Wireless communication technology | No Wireless Communication Technology |

## Product Details

- **Audio output mode:** Stereo
- **Brand:** In Phase
- **Connectivity technology:** RCA
- **Material:** Metall/Kunststoff
- **Model name:** In Phase XTB-828R
- **Mounting type:** Car Mount
- **Recommended uses for product:** car
- **Speaker maximum output power:** 300 Watts
- **Speaker type:** Subwoofer
- **Special feature:** Passive Radiator

## Images

![Car Audio XTB-828R 8" 400W Active Subwoofer with Passive Radiator and Class D Amplifer , Black - Image 1](https://m.media-amazon.com/images/I/71Mx3YPh7KL.jpg)

## Questions & Answers

**Q: How is this wired up pls**
A: you need to buy audio cables (red and black) they go to your stereo. The blue wire also to stereo. 12v from positive battery. And 0v (ground) to negative battery

**Q: Is the wiring included lilke as advised**
A: Yes all the wires were included if ever a mistake was made I would still recommend this is very reliable strongly built and gives good bass that 10x it's size

## Customer Reviews

### ⭐⭐⭐⭐⭐ Boomy compact subwoofer.
*by F***X on 18 July 2023*

Was looking to add bass to my little Suzuki Alto. As you can imagine the original two 4inch paper speakers were inadequate, so added a pair of Vibe 4inch 2way components and a pair of 6x9 which dramatically improved sound quality. However deep bass was missing and since space was a premium was looking for a compact subwoofer. The In-phase XTB828R certainly provides decent bass for the size and price. Considering it's an 8inch sub with a passive sound radiator, and comes with all the necessary wiring, you can't go wrong. One thing to note when I first installed it, the bass seemed underwhelming i.e. not loud. But adjusting the output gain from my head unit sorted that out (Not the same as volume!). Overall a decent sub to add some bass. Wont shake any windows but hey I think it works best in a small car. If you you have a normal sized car you would need a 12inch sub ;)

### ⭐⭐⭐⭐⭐ Excellent Sub!
*by B***L on 7 February 2024*

I have been using this now for almost a year, anyone saying this sub is underwhelming just have not configured it right as this thing can really rumble, the auto on feature is the reason i got this one due to not being able to access the necessary cables due to array of other devices the vehicle already has onboard but with the right amp and crossover this sounds incredible and I would highly recommend.

### ⭐⭐⭐⭐ 3 years so far, no problems
*by W***R on 28 January 2026*

Ok, I have had this for 3 years now, I have this in my off grid cabin connected to a kenwood head unit. Its size is good for me as fits nicely behind the sofa. Considering the size, the bass is quite good. No problems with it in 3 years and is used most days.

## Frequently Bought Together

- In Phase Car Audio XTB-828R 8" 400W Active Subwoofer with Passive Radiator and Class D Amplifer , Black
- VIBE Audio Slick 1500 W System Car Wiring Kit

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*Product available on Desertcart Ecuador*
*Store origin: EC*
*Last updated: 2026-02-04*