I know of transposing instruments. A transposing instrument is one where the player reads a C, plays a C, and what sounds is the name of the key of the instrument. Those instruments are often referred to with the key in their name, for example Bb trumpet, Bb clarinet, Horn in F, Eb alto saxophone, Bb tenor saxophone. Pieces for these instruments are often transposed.

I know of non-transposing instruments. A non-transposing instrument is something like a piano -- when you read a A on the staff, you play a A and it sounds a concert pitch A (440 Hz). Most string instruments (like violin, viola, cello) fall into this category.

I know of some folk/ethnic instruments, who are restricted to a diatonic scale, and therefore to a particular key. So these instruments really are "in a key"

I play nyckelharpa, which is a string instrument, and for all intents and purposes of my question, could be considered a violin (a distant relative). When I read a C, I play a C, and it sounds like a C. So that makes it a non-transposing instrument, right? It is also a chromatic instrument, which means that I can play in all keys (though some keys a bit more easy than others).

A friend plays soprano saxophone. That is a transposing instrument, pitched in the key of Bb (I looked it up). They asked me, for the purpose of jamming together, in which key I play, and I don't know how to answer that question. They know that I play a folk/ethnic instrument, and may have assumed that it is a diatonic instrument.


When in a folk jam session, they ask me in which key my non-transposing chromatic instrument (like violin or nyckelharpa) is in, what do I answer?

  • 11
    I think you're getting distracted by technicalities - what your friend wants to know is simply what key you want to jam in. Regardless of transposing or non-transposing instrument, if you start jamming on a D-Minor scale your friend wants to know so they can also play along in D-Minor. You could also easily jam in G-Major and your friend will need to know this so they can also follow along in G-Major.
    – J...
    Commented Sep 18, 2019 at 16:54

8 Answers 8


If someone is asking about the key of the instrument, I would answer "I play in concert pitch."

If when jamming, someone asks "what key are you in?" I would say, "I am playing in (name a key) concert pitch." Then everyone else will transpose appropriately. In a group with many transposing and non-transposing instruments, a discussion might be needed to find a key that is nice for every player.

  • 4
    I think answering that the instrument is “in C” would also work. Commented Sep 18, 2019 at 12:43
  • 10
    "In C" may work, but it could leave confusion as well, if someone was asking for the key one is playing in rather than what key the instrument is in. Plus, some (mainly folk/ethnic) instruments are limited to diatonic scales and can only play in one key, with several versions of the instrument for different (concert) keys. Referring to concert pitch is more accurate in the long run.
    – Heather S.
    Commented Sep 18, 2019 at 14:20
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    Yes, this. I've been in jams with bagpipes and hurdy-gurdys, and indeed these instruments are limited to diatonic scales. Commented Sep 18, 2019 at 16:57
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    @AmedeeVanGasse Meaning, technically, the Great Highland bagpipes can't play the Scottish national anthem.
    – wizzwizz4
    Commented Sep 18, 2019 at 19:54
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    @ToddWilcox - what key an instrument is in, and what key a song is played in are two different questions, +1. The confusion is the fault of the ESL querent (no offense intended OP).
    – Mazura
    Commented Sep 19, 2019 at 7:13

If someone asks you what key you play in, I take it as meaning "name a key". You say what you want, and the others will follow. If you want to jam in F#, you'll tell them "let's play in F#". Each person should know how their transposing or non-transposing instrument behaves and what to do when told to play in F#. If F# is difficult for someone, they can say "F# is difficult for me, can you do F natural instead because that's easier for my Bb transposing soprano megaphone".

To say that your instrument is non-transposing, you can say that it's a C instrument, or "an instrument in C". (According to Wolfgang H. Wikipedia, you can say that https://en.wikipedia.org/wiki/Transposing_instrument)

If you want to know what is the usual way to say "C instrument" in some other language, maybe you should ask about that specifically.

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    I am sorry, I asked the wrong question, and you did your best to answer it. I have edited my question for more clarity. It is also a translation problem, I am not a native English speaker, and on top of that, in my country we don't use C, D, E,... but do, re, me. All very confusing to do double translations. Commented Sep 18, 2019 at 8:43
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    “If you want to jam in F♯” – expect some angry stares... Commented Sep 19, 2019 at 15:05
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    @leftaroundabout +1, joined this site just to post. Playing in F# in a folk session is about as antisocial as it's possible to be
    – Joe
    Commented Sep 20, 2019 at 10:09
  • @Joe the most antisocial thing is when a keyboard played tunes down by 50ct and then proposes to jam in b𝄳 minor. (“What's the problem, your cello doesn't have frets...”) — And of course what's weird and what's common depends on local habits. Actually, F♯ wouldn't be such a far-out key for folk here in Norway – the Hardanger fiddle players tend to tune F♯-B-E-B and play usually in E major or B major. Commented Sep 20, 2019 at 10:22

If the question is about whether you have a transposing instrument (or not) your answer would be 'I'm in C' or 'I'm concert pitch'. Your soprano sax playing friend would answer 'B♭'. This might occur if someone's handing out sheet music and needs to know whether to give you a transposed copy.

If the question is about what key you prefer to play a song in (or about what key you're already playing it in!) you'd answer 'G', 'D', 'A minor' or whatever it was. You might clarify this even further by saying 'Concert G', reminding them that 'your' key is the actual key. In this situation the soprano sax player might say 'it's in my A, that's concert G'.

And, particularly perhaps as it's an ethnic instrument, the question might really be 'what keys are you comfortable playing in?' If remote keys are an issue, say so.

Is this a real situation or a hypothetical one?

  • This is a real situation. Talking about music with a friend, and they say, hey, we should jam together some time, and then they ask, "what key I'm in", before we even started about actual pieces of music to play together. They might have assumed that, because I play an ethnic/folk instrument, it is a diatonic instrument, and diatonics are indeed limited to one key, or just a few. But my instrument is chromatic, which means that I can play in all keys (although for some keys the finger position takes a bit more practice than others). Commented Sep 19, 2019 at 12:19
  • Well, that's another question again - "what keys CAN you play in?"
    – Laurence
    Commented Sep 20, 2019 at 10:22
  • But that's not what they asked. Commented Sep 20, 2019 at 12:15
  • Sometimes questions are not expressed with absolute precision :-) That's why being TOO eager to reject an answer for 'It doesn't answer the question' can be unproductive. Something that many people here could usefully take on board.
    – Laurence
    Commented Sep 20, 2019 at 22:32

With certainty, you can say that you play in C. This means, as you said, that when you have a C written, you will also hear a C.

A clarinet in A would produce a sounding A when reading/playing a C. A trumpet in B-flat produces a B-flat when reading/playing a C. Thus if you say an instrument plays in 'X', 'X' is the tone produced when he plays his or her C.


Some Irish fiddlers I've played with tuned up their violins a half step and would describe their instruments as being "in F", no matter what key the song was in, and some hardanger fiddlers I've met play in all sorts of weird tunings that heavily favor a certain key or keys.

So, depending on the type of folk music you're playing, this question could have many answers.

I generally agree with the others that your friends are just asking you to play in a certain key, and it's your job to transpose on the fly.


Most instruments can be played in all keys. In a jam session, the key of a piece is important to know, so everyone is playing in that same key!

When playing a transposing instrument (trumpet, clarinet, sax, etc.) adjustments need to be made. For instance, without dots, if the tune to be played is in do, any clarinettist (in si bemol) will have to pretend the tune is in re.

When playing on a non-transposing instrument (violin, piano), you'll play in the key stated.

If it's a jam session with grilles (charts) or dots, they hopefully will be in the correct key for the instrument. So for your 'violin', you'll read standard key that the piece is in. If the piece is in fa, you play in fa, the music is in fa. But any si bemol trumpet player will actually be playing in sol.

I've hopefully 'translated' the answer to make sense!

  • So if my friend asks "what is the key of your instrument" then my answer is "I play a non-transposing instrument so my key is whatever the piece is in". Would that be an accurate answer? Commented Sep 18, 2019 at 9:45
  • @AmedeeVanGasse - exactly. Might even reply 'whatever!' Although, if players are busking through a piece, with no charts, it ought to be enough to state what key the piece is in. Transposing players should find that's enough, and make any changes needed. You just say 'what key are we in?'
    – Tim
    Commented Sep 18, 2019 at 9:50
  • So.... I should say to my friend "what key are you in, and I will play along". Commented Sep 18, 2019 at 10:06

An instrument isn't "in a key", a piece is. If you are improvising/jamming, you can assume a non-transposing instrument to be in 'C-major', but when playing a piece, you are in the key that the piece is written in (if there is a single flat in the key signature, you are in the key of "F")

I use the key signatures of other instruments' parts to figure out if my sheet is written transposing or non-transposing (i get both, and they aren't always marked as such)

  • It is indeed for the purpose of jamming. I will add that to the question. Commented Sep 18, 2019 at 7:45
  • So the answer to my friend would be: "C-major"? Just to clarify. Commented Sep 18, 2019 at 7:47
  • One flat could equally mean key Dm, too.
    – Tim
    Commented Sep 18, 2019 at 10:49
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    Some folk/ethnic instruments are diatonic, and can only play in one key (or just a few). So these instruments are indeed "in a key". Commented Sep 19, 2019 at 12:20
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    @AmedeeVanGasse An Irish flute in D is not "in the key of D" even though it strongly prefers that key.
    – PiedPiper
    Commented Sep 19, 2019 at 19:11

If someone is asking about the key of the instrument, I would answer "I can play in any key", possibly adding "but I'd prefer to jam in [insert favorite key]".

I'd give the same answer even I have play a transposing instrument. In that kind of situation nobody else cares about your transposition. If they say "we'll play this piece in D" and you say "ok, that means I have play in E on my B-flat clarinet", that's just going to confuse things.

It's different if they are handing out parts. Of course you want a transposed part for your B-flat clarinet if they have one, but it's important to also be able to read from parts written in concert pitch if necessary.

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