A SONG OF HORNS?

This post is really only for people who've read the Game of Thrones books, so if you haven't, just ignore this. I say Game of Thrones because that has by and large emerged as the popular term to describe George R. R. Martin's universe. Blame HBO. However, real fans know that the proper name for the series is A Song of Ice and Fire, and that's what I'll be covering today. Why, exactly, is it called that? The juxtaposition of hot and cold is important throughout the books, and the title is commonly thought to contrast the fire of Daenerys' dragons and the ice north of the Wall. Moreover, in the famous prophecy telling of Azor Ahai (commonly thought to refer to Jon Snow or Daenerys), it's written that "he is the prince that was promised, and his is the song of ice and fire." Both Melisandre and the Reeds use the phrase as well. Does the title, then, refer to the prophecy? George R. R. Martin has not explicitly commented on this, but did say he was influenced by the Robert Frost poem Fire and Ice. There still seems to be a piece missing, however. Something more conclusive should draw it all together and have the name make sense- something that must be revealed in the end. My favorite theory about this is that both major horns in the series, Dragonbinder and the Horn of Winter, will be blown in the fight against the Others. Since Dragonbinder controls dragons, which are creatures of fire, and the Horn of Winter will bring down the Wall, which is made of Ice, if they are sounded at the same time, it will be a literal Song of Ice and Fire. What other purpose would the horns serve in the books? Just an interesting theory to dwell on for fellow fans.