In early 1972, Traffic was at a pivotal point in their career, following the release of their album "John Barleycorn Must Die" in 1970, which marked a significant shift towards a more ensemble sound incorporating jazz and rock elements. By the time of the live recording of "40,000 Headmen" at the Santa Monica Civic Auditorium, the band was evolving their musical style and solidifying their reputation for dynamic live performances. This concert was part of their tour promoting "The Low Spark of High Heeled Boys," which would be released later in 1971. An interesting fact about Traffic during this period is the involvement of multiple key members, including Steve Winwood, who played a crucial role in crafting their unique sound. The live setting emphasized their improvisational skills, capturing the essence of their synergy as a band during a time of significant artistic growth.