I have the 6 disc CD/DVD head unit with 9 Infinity speakers (4 tweeters, 4 woofers, 1 sub) and amp. The factory front "tweeters" are 2"(?) and crossed over by the amp at around 4khz. They are, IMO, the weakest point in the system. I preferred my settings at -4 bass, +3 mid and +4 treble. So I took my MB Quart tweeters (QTC25 that came as a part of the QM 218.61Q set from the late 90's) and installed them. These titanium 1" dome tweeters are capable of 2khz to 32khz sound production.
The install was fairly easy once I found the correct polarity of the stock speakers, since they aren't labelled anywhere.
1. Pull the rubber seal down from the A pillar.
2. Pull the A pillar trim off being careful because there is a black plastic strap attached that needs to be unhooked.
3. Pry the defroster cover up and remove.
4. Unbolt the (1/4") 7mm bolt holding the vent cover in place.
5. Pull the vent cover out from the top and remove.
6. The tweeter is there, with two more (1/4") 7mm bolts holding it in place.
Note: you WILL need a wrench or adjustable wrench for two of the three bolts, they are just too close to the windshield for a ratchet.
I cut the wires (with enough left on the plugs to reconnect later if needed). Then I crimp butt connected them to wires I had previously soldered on the tweeters, as I didn't think I could solder over my dash without burning something
As I couldn't figure out a decent way to mount the tiny (compared to stock) tweeters in the original location, I ran the wires up the corner where the A pillar meets the dash, and stuck them to the dash with double sided tape. The tweeters hide the wires from view. I left the factory tweeters in place with the plugs attached so I don't need to go looking for them if I want to hook them back up later.
The sound? Huge difference! Now I run my treble at -1 instead of +4, and the improvement in clarity is amazing! I'm VERY happy with this mod, it really makes the sound system better for a reasonably easy mod. I would suggest to anyone wanting more high range or better clarity to get a good pair of tweeters and try this install.
Tweeter wire polarities:
Front Left Tweeter:
+ Green/Violet +
- Green/Yellow -
Front Right Tweeter:
+ Dark Green/Violet +
- Dark Green/Yellow -
The tweeters I installed:
The tweeters in my Nitro: