There are conflicting theories that list either Rivera or his record producer, Al Santiago, as being the inventor of the all-trombone brass section (four trombones, in this case). An early example of this is the earliest recording Rivera made of "Askarakatiskis". This led to a more aggressive, bottom-heavy sound that was a novelty at the time. The sound lent itself well to plenas but did not catch on in salsa circles until Eddie Palmieri experimented with a similar lineup almost simultaneously (Santiago produced both artists). By the end of the decade, the all-trombone brass section was part of the standard salsa vocabulary, popularized particularly by Willie Colón, who adopted it most successfully than any other bandleader.