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How to Wire Tweeters to Coaxial Speakers (5 Easy Steps)

Many car audio fans say coaxial speakers lack high-end air and definition that separate tweeters can offer and decide to add separate tweeters to the car audio, but how to wire tweeters to coaxial speakers?

As a general rule, to wire tweeters to your coaxial speakers, you have to add an external crossover. Connect the input terminal with the amplifier, one output terminal with the existing coaxial speakers, and the other output terminal with the new tweeters you want to install.

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This may seem intimidating, but with clear instructions and a few tools, many of which you probably have on hand already, you can wire tweeters to your coaxial speakers and enjoy better audio.

If you want to do this yourself, read on for a handy guide.

What You Need to Wire Tweeters to Coaxial Speakers

To wire tweeters to coaxial speakers, you need the following tools (including our recommendations):

It also helps to have a copy of your automobile’s instruction manual handy. If you don’t have the copy that came with your car, Car Manuals Online has a thorough selection of manuals for most makes and models. Also, be sure to hold onto any instructions that come with your tweeters, as they may be helpful during installation.

Disconnect Your Battery’s Negative Terminal

Whenever you’re working with your car’s speakers or audio equipment, the first thing you need to do is to disconnect your battery because:

  • After re-installing your equipment, your electronics may also cause a voltage spike. 
  • Car electrical systems contain capacitors that may remain charged even if the car isn’t powered on.
  • If the battery remains in the circuit, static could damage your audio equipment or even your car’s Electronic Control Unit. 

When disconnecting your car’s battery, always disconnect the negative (-) or black terminal. Use your socket wrench to loosen the nut that holds the negative battery terminal cable. Move the cable to one side, making sure that it’s well away from the battery terminal.

Never allow the disconnected negative table to touch the positive battery terminal. Also, make sure your wrench doesn’t fall in a way that “connects” the positive and negative terminals. The resulting short circuit may result in your battery exploding or catching fire.

The short video below from Jay’s Garage explains in detail how to connect tweeters with car audio.

Choose a Location for the Tweeters (Sail Panel, Dashboard Edges)

Many factory speakers are installed in the doors, typically at or slightly above knee level. Other common locations are:

  • in the dash
  • in the rear deck above the back seat
  • in the kick panel located in the side space below the dash. 

Once you know where your coaxial speakers are, you can decide where to place your tweeters. Car audio experts generally recommend that your tweeters be close to ear height. But they also recommend mounting your tweeters within 12” (30.48 cm) of your coaxials so that the high and low frequencies reach your ears near the same time. 

Four popular places to install tweeters are:

  • The “sail” panel, located in the corner of your door between the car body and window
  • The outer edges of your dashboard
  • The “A” pillar between the car body and windshield 
  • The upper door

Decide next whether you want your tweeters surface-mounted or flush-mounted. Surface mounting places the tweeter on top of a surface. This strategy requires fewer modifications to your panel or dashboard but makes your tweeter more noticeable.

A flush mount is more attractive but will require cutting a hole for your tweeter to sit level with the interior panel.

If you place your new tweeters on the “A” pillar, you’ll probably need to surface-mount. Flush-mounting works best on door installations. For the dash, angled surface installations with an adjustable mount will allow you to move the tweeter to a position that gives you the best sound. 

Disconnect & Remove Your Coaxial Speakers

If your coaxial speakers are visible on the dash or rear deck, you can gently remove the grill and factory speaker.

If your speaker is held in place by sealant or foam, carefully cut it loose with a utility knife. Unscrew the screws holding the speaker in place and carefully disconnect the wires. 

Getting to your door-mounted coaxial speakers will require a bit more effort. If you have an older car, you may need to remove the window crank with a screwdriver or a window clip remover.

You can get this OEMTOOLS 25311 Automotive Window and Door Clip Remover on Amazon if you don’t have one at home. 

Today, most cars have power windows. Remove the electronic control module, which controls the power windows. The ECM is most often built into the armrest, but check your car’s instruction manual to make sure. 

Once you finish that, you should be able to remove the door panel by releasing a few retaining clips and screws with your trim panel remover tool. After disconnecting your coaxial speaker from your door, you can begin hooking up your new tweeters. 

Mount the Tweeters & Wire Them In

To flush-mount your tweeters in a car door, use a hole saw to drill a hole in the door panel that’s almost exactly as wide as the tweeter. (It’s best to do this while the door panel is detached.) Run the wire to your tweeter and connect it. Then attach the tweeter to the base cup according to the manufacturer’s instructions. 

To surface-mount your tweeters to the dash or “A” pillar, drill a small hole for the wire. Run the wire to your tweeter, then attach your tweeter to the surface mount. You’ll need to create tiny holes for the screws which attach the mount. 

To make sure your tweeter only gets high frequencies, you’ll need a crossover, such as this Audiopipe CRX-203 Car Audio Passive Crossover from Amazon.

Many aftermarket car tweeters come with inline crossovers. If yours don’t, check your instruction manual to see where your car’s crossover is located. 

If your tweeter has an inline crossover, you can connect it directly to the amplifier. Recheck your instruction manual to find your amplifier. You can hook your tweeters up on the same channel as your coaxials.

Be sure to connect the positive (red or colored) wire to the amplifier’s positive terminal and the ground (black or white) wire to the amplifier’s negative terminal. 

Alternately, you can tap into your current coaxials by running the wire to their terminals. Again, be sure to connect positive to positive and negative to negative. If your speakers and tweeters are both 4-ohm, be sure your amplifier can handle a 2-ohm load. (Most car amplifiers can).

Test Your New Tweeters & Troubleshoot Problems

Now that you’ve reconnected your coaxials and mounted your new tweeters, it’s time to test the system. Here are some troubleshooting tips.

  • If you’re getting no sound from one of the tweeters, disconnect it and reattach a short length of wire. Take a 9-volt or AA battery. Lightly touch the open ends of the wire to the battery’s terminals. If you hear a crackling noise, your tweeter is working, and the problem lies with your connection. If you get no sound, the tweeter is probably dead.
  • If your tweeter is working but still not producing sound, recheck your connections. There may be a problem with your amplifier or crossover. 
  • If you’re getting no sound at all from coaxials or tweeters, check the ohm ratings on both. If your ohmage is too low, your amplifier may blow a fuse or trip a safety circuit.
  • If you hear unpleasant buzzing or rattling, make sure your speakers are securely remounted. A loose speaker may shake, sending distortion through the driver cone.

Final Thoughts

Wiring tweeters to your coaxial speakers is not difficult, but it does require a bit of work and patience. Hopefully, this article will help you install your tweeters and enjoy all the sonic benefits. 


Crutchfield: How to Install Car Speakers

WikiHow: How to Install Tweeters

Ride Bass: How to Install Tweeters in Your Car

Drivenss: What is a Crossover and What Does it Do?