jakto'a lujvo

x1 is a note high in frequency/pitch produced by x2

cf. jarki, tonga. See also ganto'a for "low-pitched". "narrow" refers to the wavelength of a note high in frequency, as well as the characteristics of an object which produces such a note. Alternative to existing word brato'a, which is ambiguous due to the fact that "large" could refer to either the frequency in Hertz (i.e., high pitch) or the wavelength (i.e. low pitch).

In notes:

t1 is a tone high in pitch/frequency from source t3.
x1 is a note low in frequency/pitch produced by x2