Even 3 ways have their frequency cutoff. What most audio "gurus" miss when they setup, handover and tuning. It requires a good ear and the customer's preference to tune each and every speaker. The laziest / simplest way is just a direct swap.
Theoretically (say 4 speaker setup, for simplicity sake)
Tweeters should take the high frequencies
You need to know when the tweeters handover to the woofers
Swapping speakers may create overlaps and delays (phases)
Then there's sensitivity, power handling, resistance and acoustic tuning and more.
I'm just interested in good sound and am not a pro.
sorry bro, could u please explain what is ur handover?
IMHO tweeters should take high frequencies (low pass maybe from 2k hz onwards) which u r right, mid woofer (band pass from approx 50hz to few k onwards) while sub woofer (high pass below 50-60) all depends on individual preference and the restrictions of our car.
about swapping speakers, its depends on what u swap or how u swap ur speakers, by swapping ur speakers it wont change ur phase, u can check ur speakers using phase checker to correct back ur phase. about ur overlap, dun really understand.
too long never talk about ice, brains clogged already, hope all my terms are correct hehe