I'm an amateur tenor trombone player. I learnt to play by playing with other, never learnt much music theory.

I have a question regarding the "name" of the trombone. The traditional tenor trombone is the Bb trombone, or Bb/F trombone if there is a valve attachments. I understand that this name comes from its fundamental : when played "closed", this is the note played.

However, it is also a "non-transposing" instrument, and trombone parts are therefore written in ut/do/C. So trombone parts (at least mine) usually states "Trombone C".

This confuses me a lot when I try to talk about other instruments :

  • The alto trombone is usually said to be "Eb" : what does this means ? is this a transposing instruments? Are the parts written in Eb (like sax alto i think?)? Or is the fundamental Eb ?
  • I think that the sax family alternates between Bb and Eb instrument (soprano in Bb, alto in Eb, tenor in Bb, and so on). Is this the same Eb? Clearly not for the tenor : the tenor is transposing as are Clarinets and Trumpets (when they play a C, it "sounds" like a Bb).

In general, what do we mean by "this instrument is in Bb", or "in C". It seems to me that the Bb trombone is in C, which is frustratingly complicated for me. Why do we bother using the fundamental of the instruments in its name?

Edit For example, the same vending site (Thomann for example) will call :

  • A Bb trumpet, a trumpet tuned in Bb (standard). Hence transposing.
  • A Bb trombone, a non-transposing trombone (in C) but with Bb fundamental. Is this because the name for both refers to the fundamental? But that's messy because the trumpet player "thinks/plays" a fundamental C (hence a Bb in concert pitch).
  • Trombones in C and Bb are different instruments. – Legorhin Jan 15 '20 at 16:50
  • 1
    Does this answer your question? What is a transposing instrument? – Legorhin Jan 15 '20 at 16:52
  • Hi and thanks for the interest. No its not the same issue. I know that there exists different instruments. But the "standard" tenor trombone has a Bb fundamental hence named a "Bb trombone". But its also a non-transposing instrument, the parts are written in ut hence written as "trombone C" because there are written in concert pitch (the "C"). – Thomas Lesgourgues Jan 15 '20 at 17:27
  • Low brass instruments (trombones, tuba, euphonium) are "non-C non-transposing instruments". This means that while they may have different fundamentals, their music is always read and sounds at "concert pitch". The one exception to this UK brass music, which is usually written on treble clef. – jjmusicnotes Jan 16 '20 at 13:48

For trombonists, the transposition (or not) depends on the musical context you're playing in:

In UK brass banding trombones are treated as a Bb transposing instrument - parts are treble clef - see a written C - play 1st position (closed) and sound a Concert Bb

In orchestral, big band, etc., trombones are treated as concert pitch instruments. Parts are often in bass clef (though they can use one of several other clefs trombonists have to read) - see a written Bb - play 1st position (closed) and sound concert Bb.

But in general, if an instrument is said to be "In Bb" then it means that playing a written C sounds a concert Bb. Or instruments in Eb, play a written C, sound a Concert Eb.

There's no confusion if you keep in mind what sounding pitch you actually want. So instead of just saying "I'm playing a Bb", say "I'm playing a Concert Bb".

  • Ok, my confusion could come from the fact that I've never encountered your first "UK brass band" case. I've played mainly in France and Spain. And I agree with your remark " an instrument is said to be "In Bb" then it means that playing a written C sounds a concert Bb". That's why I've always consider trombones to be in C, and got really confused with all the "Bb trombones" – Thomas Lesgourgues Jan 16 '20 at 13:10

Bb- and Eb-trombones are Bb- or Eb-trombones because they are actually transposing instruments like Bb trumpets or Eb horns and because they have this root tone Bb (or Eb) when played in closed (or zero) position.

Some trombonists - are who are aware of this - can read music in C notation but then they mind that the C of orchestra pitch is position 5 (as if they would read a written D for Bb-instruments.


There seems to be also a confusion between the labeling of positions:

What we called zero position (closed position) is called position 1!

look at the posted picture, so the classical trombonist will play a C in the orchestra in position 6)

enter image description here


For brass band players who read treble clef notes, the written notes and slide positions are shown below. This image shows the notes as sharps

enter image description here

  • I'm sorry but that's still unclear. There is a big difference for me between the Bb Trombone and the Bb trumpet (as per the links provided). When in zero position, I agree that they both play a Bb, but the trombonist "knows" that he plays a Bb, while the trumpet player thinks "C". That's why (as far as I've seen over the last 20 years) trumpets parts are always written in Bb, while trombone parts are always written in C. – Thomas Lesgourgues Jan 16 '20 at 12:48
  • Is that correct? And if so. why such a difference? – Thomas Lesgourgues Jan 16 '20 at 12:48
  • This is correct for trombonists reading in bass clef and playing in orchestras. In Brassbands trombonists read the same way and with the same consciousness as trumpeters: They think they play C. – Albrecht Hügli Jan 16 '20 at 13:53
  • That's more clear! I was really confused by this "the C of orchestra pitch is position 5"... yes I also call the closed position "1", hence the C at the 6th position. FYI, at least in France and Spain every trombonist I've ever seen (in brassband, bigband, orchestra, symphonic, street music,...), all read music in C. So I wouldn't say "Some trombonists - who are aware of this - can read music in C notation". For me it's just the standard and normal way to do. – Thomas Lesgourgues Jan 16 '20 at 18:26
  • Sorry, I thought I had read here from you or someone else closed position = 0 and trying to adapt to this I used the wrong number. But I must have been wrong! – Albrecht Hügli Jan 16 '20 at 18:32

I am not a professional musician, I just want to add something to the previous answers as a (tenor - B♭) saxophone player who deals with brass sections (trombones and trumpets mainly) reasonably frequently. My interpretation might be contrary to official and semi-official guidelines for brass/woodwind sections (I have no formal training or relevant degrees).

The trombone is (kind of) like a fretless guitar. You do not have any keys, so "by definition" your instrument cannot be a transposing one. The sole purpose of making trumpets and saxophones transposing instruments is to have the fingerings identical if one switches from, say, an alto saxophone (E♭) to a tenor (B♭). The fingerings for saxophones are not linear (except for specifically-made linear-fingering instruments) and would pose a big problem for someone switching from one instrument to another within the same "family" had they not been transposed.

As far as my understanding goes with trombones, the "key" they are in, as other respondents have stated, refers to the note sounding when in "zero" (or "null") state. The only way you can really relate to most other musicians is by stating your instrument's "normal" (non-altissimo) range (keep in mind that some systems refer to the first octave as the 0 octave, and some others - 1; it's very similar in the programming world, where some languages start indices at 1 as opposed to the more "regular" 0).

Where I am, I mostly see trombone parts written in the bass clef, concert pitch, and the parts for trumpet and saxophone are written in "concert pitch" tuned to their respective instrument. So, to give you an example, if the trombone score is in C, my (B♭ saxophone) will be in D.

To sum it up, I do not consider trombone to be a transposing instrument, because it has no keys (tone holes) and functions similar to a fretless string instrument in that respect.

P.S. Languages can be very misleading. With the musical language specifically, you will often find that the same words and phrases can refer to completely different or unrelated things. Even tempo markings for classical music have to be interpreted differently depending on where they stem from. I think this is such a case. If English (or German) is not your first language, in my opinion, you will often find it difficult to understand what the hell is going on. I have studied under 3 different notation systems (4 if you take into account British English having weird names for note durations, like "hemisemidemiquaver", which is like an STD to someone who has previous experience of learning Latin and Ancient Greek).

Don't give up and develop a healthy understanding of spoken language differences and how they relate to the underlying mathematics and physics of music. If you have previous experience with natural sciences, you will also know that different countries use different common symbolics to denote the same things. It's the same with music. Treat it as another human language.

Update: following the guitar analogy, you can think of your instrument as being "tuned" to a particular note (except you can't change it by turning pegs). A guitar doesn't suddenly become a "D" instrument if you change its tuning from EADGBE (regular) to DADGBE (dropped D) - it continues to play in the same key.

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