dd doesnt make a 4500 series or a 9000 series. theres a 3500 and a 9500 series. neither would be under 5 7/8". your best bet would be the t1510''s or 1508's. my 1510s got surprisingly loudDD T1500 series, DD 4500 series, DD 9000 series.
They did make a 4500 and a 9000 series, and you can still find them floating around in the classified sections. In fact one of my buddies has two 9010's for sale on caco. They are still reconeable through dd too. the 9010's are massive little subs.dd doesnt make a 4500 series or a 9000 series. theres a 3500 and a 9500 series. neither would be under 5 7/8". your best bet would be the t1510''s or 1508's. my 1510s got surprisingly loud