External BMW Subwoofer Installation Guide for BMW F30

Want to get chills every time you are listening to some music in your car? Pairing up an external BMW subwoofer with the Alpha One Amplifier is the best way to achieve that result! And in this article, we are going to show you how to install one in your trunk and connect it to our amp using a made harness.

Coming up, you’ll learn:

• What tools are needed and how to prepare for the installation process.
  
• How to install the external BMW F30 subwoofer.
  
• Why upgrade your BMW F30 audio system at all.
  
• What else you can do to improve your BMW 3-Series sound system.

Before we get to turning that bass up, below you’ll find our video guide on this installation, in case you need some visual aids. 

Let’s Prepare! The Tools You Will Need & Safety Tips

It’s pretty easy to install BMW aftermarket subwoofer and even easier to connect them to our Alpha One BMW Amplifier upgrade, thanks to its remote-in and remote-out ports. To transform the sound of your car, all you have to do is take off a few interior trim panels. Note: although in this case we are using a sub of a particular brand, the process will look the same for all BMW subwoofers.

Enough talk – it’s time to get started. 

Here are the tools you will need for the job:

• BimmerTech Trim Tool Kit
• Torx screwdrivers (T20, T15, T50)
• Phillips head screwdriver
• Zip ties
• Electrical tape
• Double-sided mounting tape
• Heat gun

The whole process may take up to around 120 minutes, but it's not difficult with the right tools. Just to be safe, we also strongly recommend disconnecting the car battery. How to do that? Simply follow the instructions below:

1. Lift up the floor panel and take it out of your trunk. Note: don’t put it back in; you need to remove it for the install anyway. 
2. Rotate the locking tab 90 degrees to access the battery compartment on the right side. 
3. With a 10-millimeter socket, remove the negative battery terminal and set it aside. 

PRO TIP: Wrap a towel around the trunk door latch to prevent it from locking you out if it closes.

Now onto the installation part.

Step-by-Step External BMW F30 Subwoofer Upgrade Tutorial

To make things slightly easier for you, we decided to divide this guide into a few separate stages. First, we will start with the trim removal to gain access to the Alpha One BMW Amplifier and then we will install the BMW aftermarket subwoofer. Let’s dive in!

Chapter I – Initial Trim Removal   

With the battery already disconnected, we’ll start by removing the plastic rear trim panel on the lower part of the trunk gate.

1. Using a BimmerTech trim tool, pop out the four fasteners holding it down. Once the panel is free, lift it up and remove it from the trunk.
2. To gain access to the Alpha One BMW amp that has already been installed, you will need to take out the left side panel. Using a trim tool, start by removing the cargo tie-down cover, then remove all of the fasteners holding the side panel in place.
3. Remove the 12-volt socket by pulling the entire unit out of the panel and disconnecting its plug. Note: to take the side panel out, articulate it around the cargo tray weather stripping and deck lid arm and remove it.
    
   

   IMPORTANT!

   The REM-out cable will be included in your Alpha One Amplifier kit, but you will need to lengthen it to reach your external BMW subwoofer. You will also need the correct connector at the end, which is going to depend on your sub model. Additionally, the RCA cable required for this upgrade does not come as a part of the set – you have to source it on your own for the correct length. We recommend getting a high-quality one for the best possible audio experience.

4. Moving on with the installation, plug in the REM-out cable and then the RCA cable on the side. Both of them need to be fed to the back center of the trunk area since that is where we plan on placing this BMW subwoofer. 

PRO TIP: after feeding the cables through the desired location, try to secure them along existing harnesses with cable ties – if possible, you can also remove wire loom covers to feed the cables behind them. This will keep everything neat and organized. 

Chapter II – External BMW F30 Subwoofer Upgrade Preparation

The next step is to get the ground for the sub ready. 

1. Start by removing the 10 mm nut next to the fuse box. Slide your ground cable over the stud, reinstall the nut, and feed the cable through the same spot. Note: your connectors may be different, depending on how you source or make them. 
2. Pop off the cover above the battery and loosen the 13 mm nut you’ll find there. Slide the positive cable on the stud and tighten the nut back down. 
3. Feed the power cable under the side panel by taping the other end to something like a large cable tie. Pull through what you need, feed it next to the rest of the cable ties, and then tidy everything up. Note: you may find it easier to remove the cargo tie-down to give yourself a bit more wiggle room with the wire as you did on the other side. 
4. Reinstall the left side panel by articulating it into place; make sure you work the weather stripping over it as well as the lower cargo trim panel. Reattach all of the fasteners and the cargo tie-down with its cover.
5. Plug the 12-volt socket back in and snap the unit back into place.
6. Place the rear trim panel back in and,again, work the weather stripping back over it. Reinstall the fasteners and place the floor panel back in place. Note: don't forget about the cargo tie-down on the other side if you took that off during the installation. 

Chapter III – External BMW Subwoofer Installation

To prep the BMW subwoofer for installation, we have added some Velcro to its bottom side. Since this F30 is one of our showroom cars, this will allow us to remove the sub if we need to put it inside other R&D vehicles. 

This last part of the install will be really short.

1. Put the BMW subwoofer in place and secure it (you can use a more permanent solution than we did). 
2. Plug all of its connections in: RCA, positive, remote, and negative. 
3. Reconnect your negative battery terminal. 
4. Place the side cover back on, close the rear seats, and… crank up the tunes!

Great job, we are done with this audio upgrade!

Make It Worth Your While – Upgrade Your BMW Subwoofer and Amplifier!

With a BMW subwoofer in your F30’s trunk, you’ll definitely feel the car shaking anytime the sub kicks in. In this case, the Alpha One Amplifier has already been tuned for the specific sub we were x – if you also have our amp, that can be the case for you too! Just let the Alpha One team know if you plan on getting an external BMW subwoofer and they will send you the best possible tune for your setup. 

Want to improve the quality of your BMW sound system, but a trunk-mounted sub the size of a gold chest seems like too much for you? No worries! Alpha One BMW Speakers and Amplifier will already give you plenty of that extra kick. 

Head on over to our website, enter your VIN in our decoder, and get the best system for your BMW today.