Gday guys,
Yesterday I installed an aftermarket amplifier and subwoofer into my MPS 3 and it was easy!
The youtube video I made explaining most of the stuff below can be found here YouTube - How to install aftermarket amp into Mazda 3 MPS / mazdaspeed
This mod is highly RECOMMENDED because the stock bose sub sux for lack of a better word....There is no bass at all and after looking at it while it was supposedly "pumping" it didnt even move. My set up is probably 100 - 150watts RMS and it goes like crazy - especially because its a hatch. This completes the system very nicely with no more distortion or door rattle from having to turn the bass up.
What I did was take off the drivers side seat by undoing 4 bolts. Then you can access the BOSE amplifier. There are 2 clips a white and blue clip. The one on the left (white) has 4 wires going into it. Here you will tap the white wire with blue stripe(+ve) and tap the white wire with gray stripe(-ve) to get an audio signal that is pure and un-equalized by the BOSE amp (im pretty sure its a clean signal). I tapped these using some dodgy joiner clips which I picked up from Jaycar also, I would suggest soldering as a better option.
The next step is to tap the solid light blue wire on the blue clip, this is the remote signal which is 12Volts constant power when the accessory switch on your ignition is switched on. It isnt a true remote wire which only turns the amps on when the cd player turns on but its good enough and works fine.
Now run the 3 wires under the seat to under the cd player/gear stick area which is adjacent to the drivers left hand side foot well. Run it to the other side. It is easy to pop these footwells off there is a screw which you pop out and just pull out.
Now undo the footwell under the passenger seat to reveal a fuse box. Pull this towards you and then down and it will flop out. Pop the engine open and look to the left hand side just to the right of the battery. There is a mazda stencilled onto some plastic thing that you can pop off. Here there is a grommet. Run your power wire (which can be around 4 gauge) through here and get it from the passenger footwell.
You dont need wire thicker than 4 gauge unless you are running over 1000watts RMS. Remember your ground and power wire should generally be the same gauge.
If you want to run your amp into your glove box then you just pop this cover off in the back. And your wires can go right through.
Ground wire can just be bolted to the body somewhere in the passenger footwell.
The audio cable can be run from the glove box to the boot under the trim of the body just by sticking it in there with your fingernail.
Finally the signal wires you ran from the bose amp need to connect to a high to low pass filter. I purchased one for $16 from jaycar and it works soo well. You could get one from autobahn it looked the same and it cost $2 less so really no difference. On the High low pass filter you just need to attach the wires and then run an RCA cable from it to your new amp.
In the end the bose amp and STOCK SUB still work, plus I have insane bass and more of that dreaded mazda rattle
The high low pass filter is soo effective as a makeshift pre-amp that I have all the settings on the amp OFF (no gain, no bass boost nothing...) and its going hard.
p.s. no signs of over heating the amp in the glove box after running the system hard for 4 hours straight and the sub is a 10inch sony xplode so nothing special. Also JB-HI wanted to charge me $170 to tap into the Bose amp and run my new amp...it wasnt that hard lol
If you have any questions go for it, if not go out and do this mod!
MPS1