"on one note" is a correct and usable phrase in written English.
You can use it when comparing two or more items that have similar characteristics, or to refer to a single opinion or attitude. For example: "The members of the committee were all in agreement on one note - that the proposal was too expensive."
They can't just hammer on one note, either.
In many cases, a musician learning a new piece will observe that a particular run starts on one note and ends on another, and that the two are connected by a particular scale.
He'd start with a brusque four-note tune; stretch it out over an asymmetrical but catchy rhythm; stop on one note in a kind of funky stutter; punctuate the mass with a few oddly voiced but just-so chords; and suddenly the gates of Stravinskyland would swing open.
You can hang on one note for an entire song just fine if you like.
MR. BROKAW: In fairness to everybody here, I'm just going to end on one note, and that is that we continue to poll on who's best equipped to be commander in chief, and John McCain continues to lead in that category despite the criticism from Barack Obama by a factor of 53 to 42percentt in our latest NBC News/Wall Street Journal poll.
This was not Soviet propaganda, harping constantly on one note.
From the integral equation on, one notes that (2.38).
From the definition of -adic -integral on, one notes that (2.41).
"Holy mackerel, I might have to agree with Michele Bachmann on this one!" noted one person on a blog.
So politicians cannot rely on one-note speeches and advertisements the way they can take stands on Social Security in retirement communities or against gun laws in the Panhandle.
With the a cappella groups, every voice is like one string on a guitar, one note on the piano, or one cymbal, and you don't have the luxury of falling back on anything.
