Since my touchscreen radio install went for less $$$ than I had expected; I looked into increasing the high frequencies of the factory rear speakers... inexpensively.

Originally I thought to purchase a pair of Boston Acoustic 6" coaxials (they have received great reviews). But once I removed the factory Bose rear speakers, I discovered they were surprisingly good quality woofer/mid-range drivers. IMO they are only lacking in the high frequency area.

I searched for a tweeter that was thin enough to be mounted -somehow- in front of the existing speaker, but still fit under the factory grille for a stealthy install.

I read great rewiews on this tweeter; and it's only 3/4" deep (plenty of clearance to fit underneath the grille):


Here is where I mounted it - on the underneath side of the (removed) rear coupe speaker grille:


There's a wide plastic flange around this tweeter, and it made mounting - via very small screws - extremely easy. Front view before I painted the screws:


notice the tweeter sits a little high from the exact center of the grille. The speaker center does not align-up with the center of the grille; and to maximize the clearance between the back of the tweeter and the existing speaker cone (so they won't ever come in contact with each other) the tweeter is offset on the grille to align with the center of the factory Bose speaker.

Here's a pic with everything installed and the tweeter mounting screws painted flat black:


as you can see the screws blended in nicely with the grille; you can't really notice anything was modded (which was a goal of mine).

Upon removing the factory coupe rear speakers I noticed how terrible the enclosure area is behind these speakers. While I had them out I lined as much area as I could with Frost King (foil backing removed) and stuffed some foam in the nooks & crannies.

Since the Bose speaker is -roughly- 3.2 ohms impedance, and the tweeter is 8 ohms impedance, I made a custom crossover network:


here's my crude drawing of the circuit:



after testing with certain selected songs... I was surprised with this arrangement. Nice crisp & clean highs; even though this is a soft dome tweeter (which I've never personally cared for soft dome tweeters). Heck; even Yvonne said she could hear an improvement.
This is through my new radio; so I can't comment on the level of improvement they can give using the factory head unit.

Total cost for the tweeters, crossover parts, and perf boards was $44.

Although I already had coils, all these items are available from Parts Express (two of each pn):
255-024 0.2mh coil
255-036 0.5mh coil
027-330 4.0mfd cap
320-460 perfboard (a little too large, but easy to trim off the extra)
275-030 tweeter
015-1 one ohm resistor

 

Dayum Tim. You did good.

Since tweeters are extremely directional, I would have chosen an adjustable surface mount so I could point them more directly towards the front, but hey I understand what you were doing here in keeping the stealth look.

 

pics now showing again.

 

How did You determine they were of " surprizingly good quality " ..???

 

Hey Mike! Where is the sound file so we can hear how the new system sounds??




Just joking.... Nice writeup!