built in radio crossovers

i have a alpine radio with a built in crossover and a pioneer t.v. radio with built in crossover.the question is what is the deal with these are they any good i can set my crossover on my alpine at 80hz and i get a very stong bass not to boomy but when i use my pioneer and set the crossover to 80 hz the speakers sound terrible until i set the crossover to 50hz it gets clean but if i want the bass to be very strong i have to turn up the bass bosst at 50hz on my clarion crossover what is wrong here oh one is 4volt alpine and the other is 2.2volts pioneer

You are using a separate crossover (Clarion) in conjunction with the built-in crossovers on the units?  If so, use just one.  If you're using a separate crossover, feed it with a full range signal.  That would mean that the units' xovers have to be defeated.Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.