First Xover Attempt for Car

[MITMechE]

This system is for my car, one pair Vifa MG18wk09-04 installed in the doors and one pair Hi-Vi TN28 loaded near the a-pillars near the dash.

I didn't account for the mounting scheme or the relatively large offset between tweeter and woofer. Best case would be to test in-car, but that's a project for another day.

Used SPL Trace to grab impedance and sensitivity data. Only had phase for the TN28 impedance, no phase info for the response for either driver, so I just assumed phase angle was 0.

Used a Zobel on both the woofer and the tweeter, otherwise the tweeter wouldn't get the kind of roll-off on the lower end I wanted. My target was a 4th order butterworth at 2.65 khz. I used 3rd order electrical circuits on both the woofer and the tweeter and used SW to optimize the xover circuits. The Zobels were optimized to provide maximum flatness in the xover range with Matlab.

Any thoughts? I thought that generally people liked to stick with even-order electrical xovers, a 2nd order didn't seem to work with the xover freq I was using, and 4th order would require even more components.

Any tips or comments greatly appreciated. Component values need to be adjusted to standard available components obviously, but other than that I'm reasonably happy with how it came together so far.

Someone else on the PE board commented that the tweeter is only 3dB down at the XO while the woofer is 6. I used the on-axis response of the woofer, and I think being off axis in the sub-optimal car environment will result in an earlier roll off for the woofer near the XO.

[kfr01]

I think it is kinda pointless to hee and haw over the particulars here when placing the tweeters in that location relative to the driver will change the entire story at the crossover point dramatically.

Not trying to be short - just telling you how I see it.

[Volenti]

I don't bother doing any x-over design untill I have measured the frequency response of the drivers in the location they will be used, you'll also most likley need a 1k notch filter for the woofer, a spike at around 1k is very common in door speakers that cover that frequency range.