jamming

Jamming is a form of musical improvisation where players spontaneously create music together, often in informal settings without a fixed repertoire or arrangement. It emphasizes listening, interaction, and collective experimentation, with performances that can vary widely from session to session. It is common in blues, jazz, rock, folk, and electronic music.

In practice, a jam session involves musicians signaling via cues, maintaining a steady tempo, and letting solos emerge. The structure may be based on a shared chord progression or groove; players may trade phrases and respond to each other's ideas. Etiquette includes inviting contributions, avoiding overplaying, and returning to the groove after a solo. Some studios and clubs host regular open jams to help players develop improvisation skills.

Jam bands are a related phenomenon in popular music, characterized by extended improvisations and frequent live performances. The culture often emphasizes audience participation, non-standard song lengths, and a loose approach to arrangement.

Jamming also refers to deliberate interference with radio signals, typically to suppress communications. This can target broadcast stations, navigation systems, or military links. Techniques include continuous or intermittent noise, selective frequency blocking, and sweeping across bands. Jamming is illegal for civilian use in many jurisdictions and is countered with countermeasures such as frequency hopping, spread-spectrum, directional antennas, and regulatory enforcement.