I want to build a new pair of speakers and I have some drivers that I want to use, if this is possible. I have one pair of Scanspeak 18w/8535, one pair of Scanspeak 18W/8542 and one pair of Vifa XT25 tweeters. I want to build something like the "Reference plus" on this site: http://www.audiocomponents.nl/speakers/scanspeak/scan-speak_eng.htm But I want to use my existing drivers. I understand that I will have to make changes to the filter if this is a possible project to do. Any comments or idéas???