Here's a summary of what I did for anyone wanting to do the same thing. Note that I have:
- Uconnect 8.4A (not sure if there are power or filtering differences vs. 6-speaker on other versions)
- Alpine Type-R SPR-69, I trust the Type-R brand and like the slim fit and low weight of the polymer frame and neo magnet. (For the KL, slim speakers is important.)
- JL Audio C2-350x, the nicest 3.5" 2-way I could find
- Speaker adapters to plug directly into the vehicle wiring
- Cheap sound deadening (i.e. dynamat, I used 3M) added to the doors, and thin foam sealer/gasket for the speaker flanges
- Greatly upgrade sound quality, or clarity and bass, of the stock 6-speaker sound system on a KL
- Use factory speaker locations for a stealth/stock appearance
- Implement a 3-way speaker system for the front using a midbass in the doors, and shift the primary sound stage to the dash. Transition (crossover point between the dash and doors) to the midbass no higher than about 200 Hz for best blending.
(I presently run this)
- Minimal added equipment; no amps, etc.
- Passive crossovers
- Modify a 6x9 coaxial to act as simply a 6x9 midbass
- Convert the dash 3.5" from fill-speakers to the primary front soundstage
- Natural roll-off of the tiny 3.5" woofer completes the simple crossover to the midbass
1) Rear doors: easy, drop in the new 6x9 of choice
- Wire in the speaker wire harness in opposite
polarity for the 3.5". This is counter intuitive, but it will sound better since we are adding an odd-order crossover slope to the woofer in the door. If you don't believe me, try it both ways and decide yourself.
- Drop in the new 3.5" coaxial or full-range speaker of choice
3) Front doors
- Remove/disable the tweeter on the 6x9 if using a coaxial (not needed for a midbass 6" or 6x9 speaker)
- Solder and wire in a series inductor (1.0 mH for the 4 ohm SPR-69) on the 6x9 to achieve a 1st-order lowpass filter at about 200 Hz
This this setup, I like this on the EQ:
Frequency response measurement that I took after installation is shown below. It's good to below 30 Hz, which is amazing without a sub.
(I haven't done this yet)
- Drop-in new speakers
- Figure out how to separate the dash and front door speaker wiring, to run the dash/front/rear pairs as 6 channels instead of 4
- Use a 6-channel, or similar, amp with active crossover slopes
- Leave the 6x9 speakers intact, with no mods, and use active filters to turn them into midbass and achieve the same as Option A
- HPF the dash at 200 Hz, and LPF the front (or both) doors at 200 Hz
- Advantage of this is the option of doing more EQ to flatten and contour the bass response. See how peaky/boomy it is in my measurement without any, this is the nature of an in-car sound environment.