This is a complex question, but in general the answer is no. You need to know what 'field" you are in. If you measure in the near field and calculate a Xover based on this, then the far field will be incorrect. To get a correct far field you need to measure in the far field. If you only listen in the near field then you could do the crossover for the listening point, but there is no guarantee that it will be correct at other locations. In fact it is just about guaranteed that it won't.For the best coverage of this topic see my book.