The phrase "unobtrusive tones" is correct and can be used in written English.
It refers to tones or sounds that are subtle and not noticeable or intrusive. Example: The background music in the restaurant was carefully chosen for its unobtrusive tones, providing a calming ambiance for the diners.
His tone was unobtrusive, although the steel behind his move was underlined by the presence, prominent among the guests, of Pakistan's other top military leaders.
Now in his late 20s, Brendel junior is carving out a considerable reputation as a chamber-music player, to which his quiet, unobtrusive musicality and slightly veiled tone seem ideally suited.
Mr. Kirchheimer, a documentarian now in his 80s, maintains a dry tone leavened occasionally with unobtrusive music: "Brother, Can You Spare a Dime?," the labor anthem "Which Side Are You On?" His camera movements can be jarring at times, as can some confusing cross-cutting among the prints.
These are crooned by the four men in Spanish (with brief, unobtrusive spoken English translations in between) with dulcet tones and brimming eyes.
A ring tone, no matter how quiet or unobtrusive you might think it is, could disrupt the attention and work flow of those around you.
The conducting, so quiet, so unobtrusive, so suggestive, was that of a man for whom tone and a technical control of tone are matters that pass naturally his being, through all his experience and love, into music.
It's not that they help define character, but they have an unobtrusive stylishness that incorporates current key trends (pegged pants, slim jackets, earth tones) without sacrificing wearability.
He is at ease in the cool living room of his unobtrusive house on Rome's hushed outskirts, his officer-class good looks and patrician tones combining to create the impression of an orderly existence; a life well planned.
Ms. Abt's unhurried pacing and fluid, unobtrusive camera work allow the characters to breathe, and though some tough, dramatic developments are signaled early on, the tone is quietly naturalistic rather than melodramatic.
Costumes are unobtrusive.
