EXTREMELY, depending on the jumpers that come with them, and your speaker cables. Case in point:
Emerald Physics Open Baffle's weakest link was the pathetic quality of the supplied jumpers for 2 reasons
1. the pathetically cheap jumpers sounded like crap, which is a major reason why the speakers weren't more popular
2. they were too short, forcing the XOs to be placed on the bases, which shake like crazy when music is playing