Problems with Mackie SWA1801 Subwoofer and the Fix
I recently had to check the speakers on a pair of Mackie SWA1801 subs for blown speakers. Once I got the front cover off (many bolts) to get access to the speaker I found that the wire that supplies juice to the blue LED was resting on the speaker. I checked the speaker, no noise from pushing in on speaker. The problem was the wire vibrating against the speaker in use. I strapped the wire back, problem solved. I'm not sure if all the SWA1501's have the same problem, but if anyone thinks they have a blown speaker they should check the wire first.
The rest of the cabinet was put together quite well considering the cost of these speakers. I checked the amplifier side of the speaker and once I got the amplifier module off, I found everything to be in good order. This is a sealed cabinet and Mackie did a good of sealing. The hole for the wires from the amp module going into the cabinet was sealed with silicone. The only complaint I would have from these subs is the amplifier doesn't have a good enough damping factor to control that 18" speaker. The result is a muddy bottom end.