Although, after replacement, you need a signal generator and an oscilloscope / AC voltmeter to calibrate the driver levels. But if the speakers are for your own use and you don't care about the frequency response possibly being some dB off, well.. you don't care and just forget about it.
There's also the possibility of the speakers having some other faults. But if both of them are the same, it's probably this usual case of cone surrounds having split.