Carlos Santana's tone on Smooth is all about singing sustain and warm midrange. His PRS guitar through a Mesa Boogie Mark I produces a creamy, vocal-like lead sound that sustains endlessly. The midrange is emphasized heavily, giving each note a horn-like quality. The amp is pushed hard for natural compression, and the guitar's neck humbucker provides warmth without muddiness. This is a tone built for long, melodic phrases where every note sings.