What does it mean "to be in tone"?

Question

this question is only for those whose mother tongue is english please. thanks!

Answer 1

Could you possibly mean "to be in TUNE"?

Answer 2

No, for music it is "to be in tune".

The tone is the way that you talk, making your sentences sound pleasant or abrupt, happy, sad or insolent, and the way you modulate what you say.

Refering to a single instrument, you could say that a violin or a piano has "a good tone" refering to the quality of the  sound it makes and its pitch. There also is the word "timbre" which is used for the human voice when singing.

PS. You can also say that an orchestra or an instrument "makes a good sound" or "has a good tone" as a whole.

A person can have "a good ear" for music, in other words they can learn a tune easily and correctly.( tener un buen oído)