Definition of "sotto"

Jimi’s guitar plays flat against the major chord, giving a strange, almost discordant effect. Mitch on drums is behind the bass sotto.

1978–81, David Henderson, ‛Scuse Me While I Kiss the Sky: The Life of Jimi Hendrix (1983), page 104

Wolowitz: Énchanté, mademoiselle. Howard Wolowitz, Cal Tech department of applied physics. You may be familiar with some of my work – – it’s currently toodling around the surface of Mars.Penny: Hi. Penny.Wolowitz: You smell wonderful. What is that scent you’re wearing?Penny: It’s called b.o.Wolowitz: Ah. Hence the shower, of course. Leonard, where have you been hiding this one? She’s charming.Sheldon: (SOTTO, TO LEONARD) Oh, he’s good.

2006 October 2nd, Chuck Lorre and Bill Prady, The Big Bang Theory, “Pilot”, screenplay (revised first draft), act one, scene A (page 27)

Playing against the effect, Wood plays single sotto lines with a variation on the key that sustains a minor mode against the finely tuned feedback effects stroked in pinks against the upper canvas.

1978–81, David Henderson, ‛Scuse Me While I Kiss the Sky: The Life of Jimi Hendrix (1983), page 237

‘Assuming these board scores are accurate reflectors of true capacity in this case,’ Academic Affairs says, his high voice serious and sotto, […]

1996, David Foster Wallace, Infinite Jest […], Boston, Mass., New York, N.Y.: Little, Brown and Company, page 7

The twelve string rings out but Jimi’s voice is sotto, intimate.

2008, David Henderson, ‛Scuse Me While I Kiss the Sky: Jimi Hendrix, Voodoo Child, page 192