Need some audio help
 

I am replacing the speakers in my BRZ with some Infinity 60.9CS components. The door speakers work fine (replaced the stock amp) but I can seem to get any audio power to the tweeter (which will be replacing the 3 1/2" and tweeter) in the front. I have studied the wiring diagram and can see the + and - going to the mid and the tweeter. However the tweeter has four wires going to it and don't know what the other two do. Do they have to be connected some how to complete the circuit?
Any help will be appreciated. Thanks.

Possible they're getting power but no frequencies that high.

Are you installing a component set with it's own crossover or new components and using the factory wiring which presumably has its own crossover somewhere inline (I haven't reviewed the audio wiring yet). You added an aftermarket amp but kept the oem head unit? Where do you have the amp crossed over?

Was able to finally figure out the wiring. Acoustic power is delivered to the tweeter first (left hand: red - and white +) and then on to the mid range speaker. That is why there are four wires going to the tweeter. The two front speakers have capacitors on the back to limit frequency response. I removed both of those speakers and added the infinity tweeter and crossover in that location. I have the door speakers connected to an Alpine amp with the high pass filter set at 80 hz. I have an Infinity 10" Bass Link in the trunk. The sound is a quantum leap over the stock system which I found to sound very harsh.

so if I were to replace the stock tweeter with an aftermarket 1" and leave the stock 3.5" alone for now, any way I could use the stock wiring? The aftermarket tweeter would just have two wires of course

bridge the 4 pin connector(pos with pos, neg with neg) But, doing this without changing your door woofer is gonna cause problems. You would leave a gap in freq that the 3.5 used to cover. Now, if you want to keep stock wiring and amp you are gonna need to find a woofer that will play up to at least ~2khz cleanly. Put it in the door and let it naturally roll off. Then bridge the dash wiring and hook it to a tweeter with a cap to limit it from playing lower levels.

In the end tho, you still wont have something that sounds very good because of poor factory amplification. You would be best replacing the factory amp and using a 2 way component set. You can still use the door harness to deliver power to the crossover, then run a new run of wire to the dash.

Coming from the head unit, door speakers use the amp, a +/- goes into the tweeter and a +/- is passed through to the mid.

thanks for the info. Exactly what I needed. I will be replacing the amp and door speakers as well. Was just trying to be lazy and use existing wiring. Think it will end up easier to redo it all. Thanks for the diagram tho, great info

good choice.