What will fit these...help!!

Hi Everyone,

picked these up for the bargain price of 99p but what is likely to fit in them, they are massive? It maybe that I square them off and adapt the bottom end but they have, at a guess been used for something like a JBL cast flared horn but any help is much appreciated. The internal dimensions are depth of each half is 8" and the width 25" with the cut outs in the bottom being 7" in diameter.