Subwoofer and Amplifier Installation

This project adds a subwoofer and amplifier to boost the bass. It is suitable for all versions of the Model S that did not include a subwoofer, although the instructions are based on the left-hand drive cars made prior to March 2016. We also outline a number of options, as the design changes depending on if you have the Ultra High Fidelity or basic sound. The wiring harness also changed (we think around August 2013), and we describe how to handle both types of cars too.  As implemented, we avoided making any holes in the car, with the sole exception of making a small hole in a rubber gasket to feed wire from the frunk to the cabin. While this project took us about 60 hours to figure out, photograph, and install, we expect it will take closer to 10 hours of work if you follow our instructions.

As with all our projects, we do not believe any of these changes will affect your warranty. At the same time we’re also not going to take any responsibility should this not be the case and/or you screw up and damage your car!  If you’re comfortable working on cars and basic electrical/audio work, you shouldn’t have any problem with this project.

Primary Choices

There are many different sub-woofers available and related amps. We’ve chosen some we know will work and fit in the Model S and cover a range of budgets.  In the parts section at the bottom, when multiple options are provided, we used the “a” items for our installation.

NVX MVPA1 amp and Rockford Fosgate subwoofer enclosure

You can mix the “a” amp and the “b” speaker, or use the “b” choices for higher power and use a custom-designed sub just for the Model S. The “b” choices can also be purchased as an NVX complete kit of sub, amp and install kit.

NVX 1200.1 amp, install kit and sub-woofer for the Model S

In evaluating vendors, we liked NVX’s amps as they are some of the smallest, highly efficient class D amplifiers available.  You can substitute other parts if you’re partial to another brand if you find something that will fit. It also helps that NVX understands the Model S, as the company’s president also has a Model S as I discovered after selecting the NVX amplifier.

At the time of this original writing, if you do not have Tesla’s Ultra High Fidelity package, Tesla does not sell parts from that system, such as the 7.9” enclosed sub-woofer. This may have changed as Tesla has opened up the parts catalog.  It might be nice to add the Tesla sub-woofer, being well integrated with the car, but the options here will provide a deeper and higher-powered bass solution, and still retain that designed in look. Even if you could get the Tesla sub-woofer, the installation into a car without the sub looks to be more difficult than our solutions here.

While we didn’t add an amp to the main channels, if you plan to add or replace the main amp, some of the information in this modification will be very helpful, such as where to tap into the line outputs and running wires between the dash and the frunk.

Project Scope

As with most of our projects, we suggest you read through the entire installation to get an idea of different options available, different choices you may elect to make, and if this project is right for you. It may also give you a better appreciation of the efforts required if you elect to use a custom audio installer. This project was done on a pre-refresh Model S, so later cars may be slightly different. This is an unusually big project with lots of pictures, so we’ve divided it up into more digestible chunks.  Some sections can also be helpful for other projects where you need access to various parts of the car.

Part 1: Installing the Sub-woofer and Wiring
Part 2: Running Wires Through the Firewall
Part 3: Amplifier Installation
Part 4: Testing and Adjustments
Part 5: Results and Conclusions

Primary Parts List

1 – Sub-woofer (these are fitted in the trunk area of the Model S):

1. Rockford Fosgate R2S 10” Sub with loaded enclosure, 2 ohms, 200 W RMS
2. NVX BE-TSLAS-VCW104 10” Sub with a loaded enclosure designed for Model S,  2 ohms (mono), 600 W RMS

1 – Mono Amplifier (choose one or similar)

1. NVX MVPA1 Micro-V Series Monoblock Class D Amp, 300W RMS @ 2 ohms
2. NVX JAD 1200.1 Monoblock Class D Amp, 1200W RMS @ 1 ohms

1 – Installation Kit (or similar individual parts and wires)

1. NVX XAPK8 Copper 8 Gauge Car Amp Wire Kit with Speaker Cable
2. NVX XAPK4 Copper 4 Gauge Car Amp Wire Kit with Speaker Cable

2 pcs – 5 ft length of 18-20 gauge insulated copper solid wire (used only to help pull wires, will be discarded at the end)

Assorted nylon tie wraps (some are included in the NVX wire kits)

5 strips of felt 1.5″ wide by 4″ long (used around connections to avoid rattles)

Optional Items

These depend on the installation and the choices you make (see installation instructions).

• JL Audio CL-RLC Balanced to Unbalanced line converter and level control (when using line-level inputs)
• RCA stereo interconnect 1 to 3 ft, with short male connectors (when using a line converter)
• TE 1534046-1 32-pin connector (optional, from Digikey, only for older cars without Ultra-high fidelity)
• Firestone 18×8.50-8 /18×9.50-8 Inner Tube also available at Harbor Freight, Item# 61240 (for Rockford speaker)
• Add-a-fuse (for small amp power)
• Mini blade fuse assortment (only need one 30 amp mini fuse for small amp power)
• Metal bracket (depending on the amp and where you install it)
• Loctite Threadlocker Blue 242 (or similar)
• 1 metric bolt: M6-1.0 x 10mm, with lock-washers (for ground connection)
• 3 metric bolts: M6-1.0 x 6mm (or 10 mm with additional washers, for alternate mounting)
• Service labels (print labels from our labels PDF file)

Suggested Special Tools

• Electrician’s fish tape (this is a metal tape used to pull wires, such as Greenlee 438-2X Steel Fish Tape, 25′)
• Trim tool removal set (Plastic pry tools to help remove various panels)
• Soldering iron and solder
• T-20 and T-25 Torx screwdrivers or bits
• Small awl or screwdriver (under 3.5″ total length)
• Stubby large Phillips (under 3.5″ total length)
• Kneeling pads or knee pads

The links we provide are primarily to Amazon and a few other suppliers to provide more details on the item. In some cases, you might find a cheaper alternative, use a different supplier or purchase the items locally.