Guerrilla rock is loud, often aggressive music played outside the usual concert circuit—frequently in public spaces and with little notice or formal promotion. The term describes the music and the way it's made as much as the event: performances may use acoustic or folk instruments that need little or no external power, making them difficult to shut down by simply cutting the electricity. Gatherings often spread by word of mouth through social media and text messages, helping keep them spontaneous and less predictable to authorities. Some groups use portable battery-powered amplifiers to enhance their sound. The sound, audience, and mood can vary widely. A session might draw a crowd and take on the energy of an impromptu protest; another might be a handful of musicians playing in a cold park to passersby. What unites it is a DIY spirit, an unconventional setting, and music that's made on the group's own terms.
