I'm just curious, why stay away from 6x9's? From the standpoint of physics, they have some unique benefits. KEF, a high end manufacturer of home audio speakers, has been using 6x9 drivers in some of their high end speakers for many years because of their unique benefits.
I would debate the clarity issue, and here is why. I like 6x9's because of the physics involved. The oval shape prevents a variety of unwanted resonances because it is a different size across the cone at each measuring point. A circular speaker is the same diameter everywhere, and much like a bell ringing at a particular tone, unwanted resonances can, and do, develop in round drivers that the 6x9 helps minimize due to its shape. The 6x9 also has a larger surface area: 43 sq inches in true a 6x9" vs. 33 sq inches in a true 6.5" driver. Most, but not all, 6x9's will be capable of a higher SPL at a given power input due to their tendency to be more efficient than a 6.5. Even if you do not want it loud, you benefit at lower volumes by having less speaker distortion (speakers are the most distortion-producing portion of any audio system). The 6x9 also has frequency dispersion characteristics that can be beneficial compared to a round speaker. These reasons are some of the many why you see a high end audio manufacturer like KEF working with a 6x9 in a floorstanding home audio speaker.
I got over "liking" particular sounds many, many years ago as I listened to hundreds of LP's and CD's on millions of dollars of top end equipment and comparing that to live performances. Ultimately, your ear becomes trained to spot what is in common with them all, and that is what is actually in the recording, not modified or colored or altered compared to what actually is in the recording. I like reality. I like what is accurate. I like to hear what actually was recorded on the CD. Other people "like" screaming tweeters and bass that you can hear from a mile away as the car rattles all over. No thanks. I am listening to some music on my studio monitors right now.
So, what is the other side? I am talking about the physics of the 6x9, its benefits in general, and specifically 6x9's in the doors of the FJ.
Ultimately, there are other issues that need to be addressed, like physics for example. I mentioned proper crossovers, attenuation, resonances, dispersion, and timbre matching already. Unfortunately, there are multiple other issues that you cannot address listening to speakers in a showroom such as the overall reflectivity/absoption of the interior, the volume of the air space in the interior, whether any damping (sound absorbing) material is used around or behind the speakers, road noise, engine noise (always listen with the engine running because that's the way it's going to be most of the time), and so on. Fortunately, I was able to engineer my own system. It took me several attempts to get it right, but persistence pays off. So, the BEST bet (unless you want to engineer your own system like I did) is to go to a very good car audio shop and ask to hear some of their actual high end installations, not show room demos. They have trained ears, and they know what will work best in your FJ.
For me, your post is a bit frustrating. You're apparently a very accomplished listener of music and have squandered copious amounts of money owning soooooo many sets of 6 and 1/2s, only to land with 6x9s. Makes me wonder where the "science" was during that time in your life.
The Polk Audio db691 looks nice. I have owned several sets of Polk Audio speakers. Some of them have been a bit bright, and this pair may be as well because it is a "three way" with a tweeter and supertweeter. I like the mineral (mica)/poly cones a lot. I also like the 93db sensitivity. You might also consider the JL Audio C2-690tx. It's closer to a true three way than the Polk db691.
What's the way around the 4 ohm issue? Run an amp and split it off directly that way and bypass the head unit? I eventually am going to get speakers for the rear pillar, but as you mentioned it's a bit of a headache.
That wasn't my point. My point is that the 6x9 has unique advantages in the realm of physics that round speakers (specifically 6.5's) just don't have - unique enough for a high end manufacturer like KEF to use them. There is no reason to rule them out completely, especially in the doors of the FJ.
I got around it in a very unique way. I cut the tweeters to the door 6x9's leaving 8 ohms there instead of 4. Then I wired resistors in line with the dashboard speakers to lower their volume and raise their impedence. After all is said and done, I have somewhere around 3.4 ohms, which is as low as I dared to go with the stock head end unit.
Most sets of component speakers that include crossovers as part of the kit will be 4 ohms. This would be a fairly simple procedure, put the midrange (6 1/2" or whatever size you choose) in the door and the tweeter in the dash. I don't know how the speakers are wired, but you could put the crossovers in the kickpanels or under the dash on each side and tap into the factory wiring there. Anyone know the color codes and locations for the factory speaker wires?
