Phantom Center Speaker w/L-pad & bass blocker

I am looking to add a center speaker to my car audio system. After all I've read I think the Left + Right will be the best way to go for this build. I want to include a L-PAD and a capacitor to lower the volume and to block low frequency because it will be a small 3.5in speaker. How should I wire this??? My thought is that the L-pad would be in line with the positive speaker wire with terminal one grounded to the chassis, terminal 2 from the left positive speaker lead, and terminal 3 to the positive of the speaker. I think the negative of the speaker would go directly to the right negative lead. Does this sound correct? Where do you think the bass blocker should be placed? Before or after the l-pad? Any other suggestions would be greatly appreciated and I would love to start a conversation about different options. Thanks!!
Can you find an L-pad that's for use with the speaker you want to use. An L-pad is used to preserve the impedance of the system as well as allow the adjustment of the level.

Nothing connects to the chassis. The 'ground' terminal of of the L-pad often has 2 terminals so you can connect the the negative signal wire and the negative wire for the speaker.

If you find an L-pad of the proper value, the crossover goes before the L-pad.