This may sound like a silly question, but bear with me I'm relatively new and self taught What is the purpose of altered tunings? I thought the whole idea was to form different chord shapes in different places. However, last night I was trying a few songs from a Smashing Pumpkins songbook. They used a drop D tuning. However the chord diagrams (eg. for a basic G chord) were the same as I'd use for a standard tuning. So is the idea of them to form the same chords, but make them sound different? Surely though with a different tuning thats not a G?