Slightly OT: How do you notate an open key signature?

I am working on a score that goes between major/minor keys and open keys.

As a percussionist, I never really worried about keys so much, as I just played the notes on the page. But I am wondering from a conductor’s point of view/rehearsal point of view. With a score that goes back and forth so much, should I make a textual description that the music is now in an open key? Or should I just leave it alone?

I have been in many rehearsals where the conductor states, “Let’s begin at the key change after M”. This issue with this, is that if the instrument was in C (no sharps/no flats) at M, the open key after M doesn’t show an indication of a key change, other than the double bar. Currently I have been placing a boxed text stating “Open Key”, but I am wondering is this is really worth it or not.



Put extra rehearsal marks or bar numbers at those points so the conductor will use those. I can’t see any reason why ‘open key’ should cause trouble, so fine to have it.

Thanks for the feedback. I appreciate it.


The thing is, unlike time signatures where you can write an explicit X for “open” if you want, there is no standard notation for an “open/atonal key signature” that looks different from “C major”.

As such, it doesn’t make much sense for a conductor to refer to “a key change” unless the number of accidentals printed in the score and parts changes at that point. It might be “obvious” looking at the score that the music has changed from “tonal C major” to “atonal”, but not necessarily obvious from looking at one player’s part (extreme example - the change is in the middle of a long rest!)

There is also the issue of transposing instruments where (for a Bb instrument) a key change from concert Bb to “atonal” would be invisible even if non-transposing instruments could see the two flats being cancelled.

Not to mention the traditional orchestra notation for French horns with no key signatures at all.

Steve Parker’s advice is good and practical, but I’m not sure this is a major issue in real life.

Scores where there may be changes between “tonal” and “atonal” sections, like movie soundtracks, are often written entirely without key signatures, to sidestep the issue - and it is claimed that this also improves sight-reading accuracy, at least for musicians who are used to the convention.

That is exactly the issue that I am running into… a Bb Trumpet. Couldn’t tell from the part if there is or ins’t a key change.

I also agree about there being no standard, as is with Time Signatures. That was why I was curious if placing a boxed text stating “Open Key” or something similar was a good idea. Or is it better left alone, believing that the conductor would never say such a statement.

The piece I am currently working on is an arrangement/transcription for wind band from a pretty well-known work. Sadly the arranger/transcriptionist passed away several years ago. I am unable to ask what was his thought was on some of his choices. To add insult to injury on this piece, the hand written score has numerous key changes, however these key changes do not align with where the part shows the key change. So there is a lot of confusion all around with engraving this project. I am just trying to finish piece in such as fashion that makes the most sense for everyone (players and conductor).


Nobody should be using key signatures in the 21st century… Heh, heh, heh, heh!

I think it could lead to confusion if suddenly the trumpets, alto and flutes all have the same (empty) key signature, so I would use ‘Open Key’ and explain it somewhere.

I think there is no standard because there is no need for it IMHO.
From a player’s point of view, the notation changes from “some signs at the beginning of the line and some signs within each bar” to “no signs at the beginning of the line and more signs within each bar”, but that has no influence on how the notes are being understood.

(Think: There is also no sign to indicate if a piece is in a major or in a minor key, so why indicate atonality?)

On the conductor’s sheet of course, a little indication will be appreciated, but that’s all I would do.

(BTW, I strongly oppose saying things in rehearsal like “we start from the key change after B”, because of the poor drum players who don’t see them at all. :smiley: )


I couldn’t agree more with everything you have stated. The more I think about this ‘issue’ is I am really realizing that my whole concern is from a rehearsal issue, not a player playing music issue.


If I’m not mistaken though, DORICO does differentiate just like going from metered to open meter, so you may still want to put it into the score even though it won’t display a key signature. (It might influence what accidentals are generated for instance. Someone can correct me as I’ve been away from my computer at a conference all week.)

The most obvious thing it influences is the key signature displayed (or not displayed) for transposing instruments.

How Dorico decides whether to notate a chord that you play on a MIDI keyboard as F# major or Gb major, when the key is either “C major” or “atonal”, is a whole different topic from the OP’s question!