It sounds like you're looking for an underlying reason for both tweeters blowing at the same time, but it's much more likely that you just didn't hear the first one until the second one went out. How old are they?
And when you say that the crossover and amp are good, what tests did you run to verify that?
Engine Mods: 3SX headers + test pipe + SS catback, K&N FIPK, Kevlar Belt + Solid Tensioner, Polyurethane Motor Mounts, Aluminum Crank Pulley, '99 Lifters, VSS, Fuel lab filter/SS fuel lines, fuel rail fuel pressure gauge, custom SS fuel sender assembly studs, MSD 8.5mm wires + Accel coilpacks, Stage II Spec clutch, clutch damper delete, evap delete
Suspension: Complete Polyurethane subframe/suspension, Addco Front/rear sway bars w/ Moog endlinks, front/rear strut bars, Vogtland lowering springs, KYB struts (ecs delete), Copper/Nickel + SS brake lines + abs delete, EBC green pads/drilled+slotted rotors, rear adjustable control arms w/ chromoly heim joints
Aesthetic/Weight Reduc: Blue Wire Mod, 17" Motegi Racing MR131 rims, Clear Timing Covers, HID 6000K headlights/Fogs + LED hi beams, CF hood, aftermarket seats, 1200W Sub/3000W Amp/Samsung Tablet h/u, Acrylic Enamel Caracas Red paint, 99' sail panels, Spark plug cover, tan to charcoal interior