It is best to use an active highpass filter for the mid-bass and higher frequencies amplifiers and use an active lowpass filter for the subwoofer amplifier.
Linkwitz-Riley filters are the best.
I think adding two power transistors to the power supply rails of a little TDA2030A amplifier IC is a Mickey Mouse way to cool the IC but it works. The output power is not much higher than an ordinary car amplifier IC and it needs a complicated switching power supply.
Philips has some class-H power amplifier ICs for cars that have a built-in supply voltage doubler. Then it switches its supply voltage to the output stage to the boosted voltage only when required to stay "cool" (so it doesn't melt). Their TDA1562Q produces 55W into 4 ohms at 0.5% distortion when the supply is 14.4V. the power is 45W when the supply is 13.8V.
Good luck making your own very complicated switching power supply for the other amplifier ICs.
Linkwitz-Riley filters are the best.
I think adding two power transistors to the power supply rails of a little TDA2030A amplifier IC is a Mickey Mouse way to cool the IC but it works. The output power is not much higher than an ordinary car amplifier IC and it needs a complicated switching power supply.
Philips has some class-H power amplifier ICs for cars that have a built-in supply voltage doubler. Then it switches its supply voltage to the output stage to the boosted voltage only when required to stay "cool" (so it doesn't melt). Their TDA1562Q produces 55W into 4 ohms at 0.5% distortion when the supply is 14.4V. the power is 45W when the supply is 13.8V.
Good luck making your own very complicated switching power supply for the other amplifier ICs.