Older Honda Accords have rear deck mounting holes for 6 X 9's. However, they are not my favorite type of speaker (why waste the power to run tweeters in the rear of my vehicle (high pitches are so directional not a lot of the sound is going to get to the driver and sound nice)). So this little hack will let you mount a pair of 6 1/2'' speakers in the rear of your vehicle.
Step 1: Collect Materials
All you need is:
1.) Speakers - the 6 1/2 variety
2.) Bolts - 8 - 32 fits well
3.) Nuts - make sure to get nylon lock nuts
4.) Female spade disconnects
if you have the speakers it will only cost $7.50 but if not it will be a bit more expensive.
Also, now is a good time to remove those covers for the rear speakers.
Step 2: Cut Holes
Essentially all this is, is bolting the speaker directly to the speaker cover.
Step one is flipping the cover over and then placing the speaker cone down on top. Ensuring that the terminals are in the correct direction dry fit three bolts into three mounting holes, it may take a couple different positions and a bit of wiggling (or drilling if you want) and the bolts should fit through the squares in the cover. The bolts will now be disturbing the fabric on the other side so flip up the cover forty-five degrees off the table and using scissors cut a slit that the bolt can be pressed through.
Step 3: Bolt It
Now all there is to do is take the bolts out, flip them around, and push them back through - this will create a flush and better looking finish.
You will need a screw driver and a wrench (or socket) to tighten the nylon lock nuts, but it is worth the effort because these guys will not shake loose.
Step 4: Spade Female Connectors
To wire the speakers up, the car will need female connectors for the terminals. Luckily this is super easy to set up. Simply strip some of the positive and negative wire either run from your head unit or amp and stick this wire into the insulated hole in the bottom of the connector. Make sure that the wire is touching the metal ring on the inside and then squeeze it all together with a pair of pliers.
Step 5: Try It Out and Have Fun!
The base idea here is: to convert a 6X9 mounting hole to 6 1/2 speakers just bolt them straight to the roof (cover). In different cars it may require some drilling, but however it is done the finished result will be worth it :)