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Among the extended techniques that occupy such an exalted role in the vocabulary of free improvisation, rubbing and scraping may seem humble, but they’re vital all the same. Obviously many instruments are played by rubbing their strings with a bow (what those in the biz call arco), but an infinite number of objects can be rubbed or scraped to produce a surprisingly wide variety of sounds–it’s common, for example, for a drummer to bow his cymbals or rub a moistened finger across a drum head to create evocative whines and moans. The Chicago trio called the Friction Brothers push this idea to an extreme: on the group’s self-titled debut, released by the Pittsburgh label Abstract on Black, all the sounds are generated by some kind of friction.

It reads almost like an absurdist joke, and if it were only about making weird noises in unusual ways, it’d sound like one too. But the Friction Brothers’ ensemble sound is diverse and extremely tactile, blending resonant long tones with abrasive blats, and the three players coax all of these noises out of their hardware in the context of a deeply intuitive spontaneous musical conversation.