Complex sentence: In practice, higher orders increase the spatial resolution (which reduces crosstalk between speakers but also requires more speakers to reproduce correctly) and enlarge the area where the sound field is reproduced perfectly (up to an upper boundary frequency).
Split into simpler sentences: In practice, higher orders increase the spatial resolution, but also require more speakers to reproduce correctly. Moreover, they enlarge the area where the sound field is reproduced perfectly (up to an upper boundary frequency).