Headrest speaker installation in a (NB) second generation Miata.

You might also want to check out M2 OEM Sound system FAQ before starting anything.

The lack of headrest speakers in the second generation (NB,M2, 99+ etc.) Miatas makes it hard to hear sound with the roof down.

My friend Bert has an Evo Orange 2000, with the 4M32 factory radio and missed the headrest speakers on her 90, so we decided to add speakers to her car.

Here's what we did:


Life in 21st Century America Disclaimer:  I am not a professional mechanic, or audio engineer, although I do play one on the web. ;-)  I make no warranties or guarantees that any of these procedures can be done without causing harm to you or your vehicle.  If you injure your car, yourself, or your neighbor's cat,  following, or attempting to follow these instructions, don't come looking for me as a responsible party.  You are on your own.


First remove the seats from the car.  14mm socket, 4 bolts per seat.  Mazda torques them to like 10,000 pounds/inch, so use a good 6 point socket, and a breaker bar.  You don't want to round these.

Lift the seats out of the car.  Take care not to scratch the car.  Windows and roof down before starting help. If you're working a garage, make sure you have enough room to open the doors all the way without banging into walls.

You need an 8mm socket to remove the bolt holding the seatback to the bottom of the seat, on the inboard sides.  To disconnect the outboard side, use a Phillips head screw driver to remove the screw in the center of the round part just to the rear of the seatback adjustment handle.  After removing that screw, gently bend the plastic down exposing another Phillips head screw holding the plastic cover the seatback portion of the recline mechanism.  After removing that screw, slide the cover upwards, and remove.  This will expose two 14mm bolts holding the seatback to the recliner mechanism.  Remove the 14mm bolts, and work the seat back loose.


There is no need to do anything to the seat bottom.

There are bunches of hog rings holding seat back material to the seat back cushion.  We are are going to cut those off with wire cutters and remove them.  If you start at the bottom of the seat back and work your way up, it's pretty obvious where they are.



After removing all of the hog rings, and taking the skin off of the seat, the fun really begins.  If you have purchased fairly shallow speakers, you can lay them out side by side, trace them onto the foam, and then cut it out.  If you have purchased the MAX-5 speakers from Performance Buyers Club, as we did, they are very deep speakers.  The sound great,  but due their depth, if you opt for a side by side mounting, as one would normally expect for stereo, the backs of the speakers will not clear the steel bracing holding the seat together, forcing the speakers to protrude from the front of the seat.


Since we were shooting for top down sound, and not necessarily concert hall reproduction, (which ain't gonna happen in a convertible anyway)  we already had the speakers, Bert was out of the country, and I wanted this job done, I decide to punt, and try to find another way to mount the speakers.  I chose to mount them vertically.  It sounds good.  They fit.  If you really want left/right sound, get another brand of speaker, and you're good to go.  You have about 1 1/2" of depth before you hit steel.  The MAX-5's are about 2" deep


PBC also sells a harness for adding speakers to NA Miatas not originally equipped.  Buy it. You want the long harness.  It includes the very important plastic connector the attaches directly to the factory radio, eliminating hours of trying to build a harness from scratch.

The thing I didn't like about the PBC harness is that the harness runs directly from the radio to the speakers.  Mazda, in their NA factory equipped version, runs the wiring from the radio, to a clip under the seat, and then to the speakers. It allows you to remove the seats should you need to, by simply disconnecting the clip.  I had a bunch of 4 conductor power connectors for computers lying around, so we cut the harness under the seats, and soldered in the PC connector clips. These are the connectors used to power hard drives and other peripherals in desktop computers. If you don't have some laying around, Radio Shack sells them. Can't cost more than a buck or so.


Back to the speaker installation.  After you have resolved the left/right  up/down dilemma, trace the speaker outline onto the foam.  Get out your trusty Swiss Army knife, and cut the foam out where the speakers are going.  Cut smaller than you think, you can always cut more.  Putting foam back is trickier, but if you do over cut, it's probably not the end of the world. You can always stuff some back in.  Duct tape the over cut foam in place.  If you didn't over cut, you don't have to tape anything. ;-)

Punch a small hole through the back of the seat, and pull the wires through, to the back of the seat. Run the wiring down the back of seat. I used needle nosed pliers to reach through the puncture, grab the wires and pull them through.

Double check your connections to the speakers themselves, and make sure you are comfortable with the speakers position.

We used nylon zip ties in place of hog rings to hold the skin to the seat.  I've done it before on other seat projects, there have been no long term problems, and it's a hell of lot easier than using hog rings.  It's a lot easier to put the zip ties through the wire in the seat foam before putting the skin back on.


After you have inserted all of the zip ties, put the skin back on the seat, over the speakers, you can start from the top, and working down, pull the zip ties tight, and trim the excess zip tie off with wire cutters.

It's now time to put the seat back onto the seat bottom.  Assembly, as the British car manuals say, is the reverse of disassembly.

Solder the PC connector onto the wiring.  Use a zip tie to hold the wire in place on the bottom of the seat.

Repeat for the other seat.


After both seats are ready, and while they are still out of the car, solder the other half of the PC connector to the rest of the wire harness where you cut it.  Locate the factory cut in the carpet under the seats, toward the front of the seat area. Using a fork, or the handy dandy patented Wizco Carpet-O-Matic (piece of metal that came with some piece of furniture with a groove cut with a hacksaw) tool, remove the fasteners hold the carpet behind the seats.

 Run the wire through that cut under the carpet to the rear of the car. Then up towards the console along the rear bulkhead.  Lift the edge of the console, and work the wire under the console towards the front of the car.  It may make it easier if you loosen the screw under the ashtray. Continue tucking the wiring under the edge until you reach the end of the plastic trim.  At this point, you are well under the dash.

Repeat for the other side.


At this point, you have two wired seats outside of the car, and wires run from the footwell, under the console to the rear bulkhead, under the carpet, and you have about 6" of loose wire attached to the PC connector showing form the hole in the carpet.

Disconnect the battery. 

Gently pry off the tabs on either side of the radio.  If the car has a cassette player, it will make life easier if you remove it as well, so take the tabs off of that as well.

       ( A really detailed article, with better photos on this radio can be found here.)

This will expose 2 holes on either side of the radio (cassette deck as well).  I have a cheap set of radio removal tools, that  I bought at Circuit City al long time ago, but others have used coat hanger pieces cut to 4" or so.  Insert the tools into the holes, unlocking the radio.  Pull it out.

If you have big hands like me, pull the cassette deck, disconnect the one plastic pug attached to it, and put it aside for now.  If you have small delicate hands, or just a glutton for punishment, leave it in.

Pull the radio out. Disconnect the antenna by pulling the plug straight out.  Disconnect the ground plug, and the other 2 white plastic plugs.  You can't mix them up putting it back together, (they won't fit) so don't worry about keeping track of what's what.

Set the radio aside.

Get a coat hanger and pull the wire harness from the headrest speakers up into the console.  Plug the headrest speakers into the back of the radio, in the only place it will fit.

Reinstall all of the other connectors to the radio. Slide the radio back into place until it locks. If you pulled the cassette deck, you can maneuver the wires out the way of the radio on the way in.

Reconnect the wiring to the cassette deck.  Slide it back in until it clicks.  Replace the trim tabs.

Reconnect battery.

Put the seats back into the car.  Connect the PC connector halves together.  Bolt the seat back into place.  Check to verify the wiring is not pinched, nor will it be pinched by the movement of the seat.

Turn radio on, adjust fader to your taste.  Reset the clock.

Go for a drive.

(Total work time including inventing, and a parts run, 11 hours.)