[ChrispyGER]

Got it.
Yeah, I don't want to have the same audio experience on every seat. I learned that me sound file was the wrong, after I added the HK tweeter. Because vocals come way more from the front (for my taste). I learned that I have to change / adjust mix between the center and front left.

I understood now, that the HK tweeter can improve audio quality because there is now an additional tweeter. But mix between all tweeters is the key.

[NealfromNZ]

Originally Posted by Billfitz

And that's the problem for everyone other than the driver. When your ears are a foot from the radiating plane on one side and four feet from the radiating plane on the other side there's only one spot in the car where you can get reasonably good stereo imaging, and that's the one you're sitting in. Everyone else is out of luck. The purpose of the center speaker is the same as that of the rear door and rear deck speakers, to make the sound more tolerable to all of the passengers. Perfect? No. It's not Carnegie Hall, it's a car. To paraphrase Harry Callahan, 'Man's got to know his (car's) limitations'.

That’s the beauty of dsps, you’re not limited to having just one map or seating position. You just flip maps / time alignment depending on car occupancy .

In the earlier days of car stereo competitions (90s) you’d have two judges sitting in the front. One of the techniques used to help centre image for both positions was putting a second set of left and right tweeters with a lowish crossover point in the middle of the dash. It actually help quite well.