Where did your brother install these? No offence but I think the a/d/s/ he has bought are all fake 'china a/d/s', not the real analog digital systems from USA. In 2006, the importer from Johor was caught, fined and it was in the newspapers.

The real a/d/s/ never made those model of amps nor crossover and the a/d/s/ 236is and the sub is an old model which was copied somewhere in 2005-2006. Check them out yourself at http://www.adst.cc/

The real thing is at http://www.adst.com/