It's a pain alright......the newer, more streamlined cars have much wider rear decks than the "good" old days......I'd like to see one of the manufacturers start using 8" round coaxs in the rear, with the right amp most people would think there was a sub hidden away somewhere.......

The worst ones had to be the 4" X 10" whizzer cones GM put in the Le Mans or the Cutlass coupes back in the day.....yikes!

I would suspect that the average listener in a car would not have the tunes loud enough to cause those issues with oval speakers to be very audible. Considering the cone area for a 6X9 is pretty close to an 8" round speaker it will move almost as much air, and oddly enough the oval shape seems to be holding it's own with almost all the vehicle makers due to space restrictions in certain areas.

It's only us car audio junkies that discover these little problems.....

 

That's exactly the reason for the oval shape, to equal the same cone area as a standard 8" speaker, but of course, 9 watts RMS off the deck isn't really going to move much air...

 

you should check out Image Dynamics X69 midbass with cd1 horns, very efficiant you dont need much power but they are VERY loud although a little harder to install. Neo magnents as well so shallow

 

If you are driving a Ford and the factory size is 5x7", then a 6.75" speaker can go there with the proper abs mounting template adaptor. This will also add 1/4" of extra mounting depth as well. Another option here is to use the Eclipse 5x7" pointsource speakers. The tweeters are removeable should you want to make them a true component speaker. They sound amazing and are budget friendly as well.

As far as the drivel that you read about the distortion of a oval speaker goes, what is measured and what you hear are two totally different things. I know these speakers sound good, this is why I would recommend them.