Alright so I finally have everything installed in my 99 Bravada.

I have:
Pioneer AVH-4500BT HU
Polk Audio db6501s components in the front (tweeters mounted where the old ones are)
Polk Audio db651s coaxials in the rear
Precision Power i520.4 amp. 100w 4-way (Gain turned to about 3/4 on front and rears)

I did the whole installation by myself but I can't really get a decent sound.

The highs are coming out very harsh and I think the driver side sounds harsher than the left even with -3db reduction on the tweeters. (Maybe it's out of phase?) I don't really want to mount the tweeters in the speaker because I'm not sure if it'll fit with the stock grills.

Any advice? Where do you guys mount your tweeters? Also I've tried EQing but I can't get it too sound right.

 

Where to start? lol... There's so many things that can contribute to your issue it's tough to really nail down exactly what the issue is without being there in person, but I can recommend some things to try.

First and foremost to start with is to verify everything is in phase. Once you're certain everything is in phase and the problem wasn't related to that try changing the phase one speaker at a time. See how that affects the sound and go from there. While you're at it disconnect the mids and listen to just the tweeters, then disconnect the tweeters and listen to just the mids. Find out if it's more relevant to one or the other.

I would also try removing the tweeters from the factory location, make sure they have plenty of wire, get yourself some double sided tape or something similar and try moving them around. Keep them on the same plane, or at the same height and try to keep the direction they aim the same as well as you move them around. Glass has a high resonant frequency and is really horrible to have any high frequency driver firing at. Moving them around can show you where they sound the best and the worst at. Then you can decide what kind of compromise you want to make as to their placement, how much work it's going to take to put them there permanently, and ultimately the sound you're going to get from them.

How do you have the mids mounted to the door? I find having them behind the factory plastic baffle really hurts the response. Getting rid of the factory grilles may not be an option for you but keep it in mind. The most important factor as to how any speaker sounds and performs is in it's installation. A solid mounting surface that is as acoustically dead as can be done in a vehicle is the ideal perfect thing to mount the mid to. Bass and midbass are powerful and if the baffle the speaker is mounted to moves easily to those forces then output and clarity is lost. A flimsy baffle will also resonate easily and that can and will interfere with the midrange frequencies. Make sure you give the mid a solid baffle to mount to coupled with some strategically applied and used sound deadening.

All these things can help ensure you get the most from your setup. Try some of these things you've not already done and come back and let us know if you need more help.

 

Thank a lot! I'll work on it later today and let you guys know what I found out.

 

I planned on buying the 651s for my door and rear speakers, lemme know if you get them sounding good. You might just have the gain too high.try no gain and creep it up.