And just how is someone who barely knows which end of soldering iron to hold supposed to ascertain all the parameters which go into making a functional crossover?
For all but the most basic cookbook crossover, which has an extremely slim chance of being correct for the drivers, it takes sophisticated equipment, knowledge and experience to be successful.
Comments like the above are the reason there are so many egregiously awful designs extant. Designing a decent loudspeaker is many times more difficult than designing decent electronics.