Singing the Psalms

I've been thinking a lot about give praise to God, and it's discussion of singing the Psalms. This book seems to be a massive untapped asset to our music ministries. Why not sing the songs the Bible already gave us? I've also been considering about what the author had to say about choosing appropriate tunes. He says they need to carry weight and majesty(273). I've been struggling what the author means by this. He calls many tunes prissy and frivolous and I'm not sure exactly what he means. I think that the style of music should appropriately carry the text. Does weight and majesty mean everything has to sound like a mighty fortress is our God?