Classical music in Iran became formalized during the Abbasid dynasty (750 – 1258 A.D.), but due to Islamic suppression, it didn't reach too many beyond royals and the wealthy until the 1900s. The music itself revolves around memorizing and mastering a series of melodic passages, and is played on lutes, flutes and the dulcimer-like santur, often accompanied by improvised free singing.
Avey Tare: I've been getting into a lot of Persian classical music lately. Like santur music or some more Sufi singing stuff. I think a lot of that's got me a little bit more interested in more of the documented side of music, or notated — certain notes are used for a specific reason. I guess for that type of music it seems very religious or spiritual. And I'm not specifically getting into it for spiritual purposes but I think it's just interesting to think about music that has all this deeper meaning to it, in a numbers way, or letters, symbols.