Sometimes you hear something new and your perspective on music shifts seismically, making everything you were listening to previously sound safe and predictable by comparison. Inevitably, as one gets older and more musically knowledgeable, such moments are fewer and further between; either the shock of the new isn’t as high-voltage as it used to be, or it just irritates rather than stimulates. And so it was a pleasant surprise when, one morning – heralded by a storm of tape hiss and an enthusiastically bashed tribal drum – a new band called tUnE-yArDs (aka Merrill Garbus) came at me from the hi-fi speakers like a Dadaist, feminist pop warrior.