Here i am testing how the speakers sound using different crossover's. I did a similar test when i built the daughters system a few years ago. Testing out how tweeter perform with different crossovers.
Left side is the Focal crossover that came with the speakers. Right side hooked up to a RF T2 6.5 crossover. With the HU set to 0 on treble,mid range and bass adjustments these 2 speakers sound night and day from one another. Its not just there crossover points,which is to be expected, but the clarity, range and dynamics.
The technology that is in the RF crossover seems to make a improved performance to the speaker with all variables being the same.
The 4" JBL GTO 429's above the RF crossovers were tested out. If the a-pillar didn't have the stock tweeter location with grilles in them than i think a really good set of coax on axis would work in dash pods. These drivers how ever are a bit to bright for my liking and i would not use them even if i could. I know Morel & Hertz have some good 4" coax with great tweeter designs for performance.
Better view of whats going on in these 2 crossovers. I know crossovers are designed specifically to the drivers that go with them. I get that the FOCAL crossover points will be higher for the 3.5" driver(100-120hz HP) where the RF crossover is designed to work with a 6.5" driver so HPF is more likely 65-80hz. There seems to be more power and clarity with the RF. Tweeter sounds great where it is not even noticeably off the Focal crossover. All just interesting observation with playing with these different drivers. More to come!