need help what driver in this basshorn


i will build this bass horn http://aphrikka.freetekno.cz/909/HB1805C1.jpg and i dont know what driver put into it ... i chose Fane colossus 18B-600 ....
can anybody tell me if its correct or tell what another type of driver //i can buy fane, precision devices /not pd 1850 its best but too much expensive/ ,BC,or DAS// ?????
thnx very much


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