Salsa jazz: where the dance floor stops and the solo starts
How salsa and jazz combine: the montuno as a constraint on the soloist, why walking bass will not fit, harmonic movement a dance band would avoid, and how to tell the two apart.
Salsa jazz keeps the Cuban rhythm section and imports jazz harmony and extended soloing over it. The important consequence is that the pianist plays a fixed montuno rather than comping freely, so the soloist rides a moving floor instead of being followed by the band.
Soloing over a floor that will not follow you
In a jazz trio the rhythm section reacts. The pianist changes voicings in response to a phrase, the bassist redirects a line, the drummer answers a rhythmic idea. In an Afro-Cuban rhythm section almost none of that happens. The piano montuno cycles, the bass plays its tumbao, the congas hold the marcha, and the soloist plays over a floor that is going to keep moving regardless.
Musicians who cross into this from straight ahead jazz usually describe the same adjustment: you stop expecting to be caught, and you start building lines that ride the pattern. Long, even quaver lines work. Rubato phrasing does not.
Harmony a dance band would not risk
The other half of the fusion is harmonic. A dance salsa chart keeps the changes simple in the montuno because the floor needs stability. A salsa jazz arrangement can move the harmony under the same rhythmic bed, reharmonise the vamp, or run a sequence through several keys, because nobody is being asked to hold a partner through it.
That is the practical difference to listen for. If the percussion says salsa and the chords keep moving, you are in jazz territory.
Length
Salsa gives a soloist sixteen or thirty two bars and hands back to the coro. Salsa jazz gives a soloist as long as they can sustain. If the trumpet has been playing for three minutes, the piece is not organised around a dance floor.
Good listening order
If you are new to this, start with cha-cha-cha based heads, which are the most transparent, then move to mambo tempo material, then to anything that mixes a bolero opening with a montuno section. The Latin jazz guide covers straight quavers, the two families of Latin jazz and why the subdivision change matters more than any other single factor.
The Salsa Jazz Instrumental playlist page covers when to put this on rather than what it is.