What Are Bb and Eb Instruments? Transposing Instruments Explained
Bb and Eb instruments are instruments where the note written on the page isn't the note you hear. Play a written C on a Bb trumpet and what comes out is a Bb. Play the same written C on an Eb alto sax and you hear an Eb. They're called transposing instruments, and the letter in the name tells you what a written C actually sounds like.
A new trumpet player comes to rehearsal. The guitarist says "it's in C," the trumpet player plays in C, and the room instantly falls apart. Both of them are right. They're just speaking different languages. The guitarist means concert C, the trumpet player means the C on their page. The gap between them is a whole step.
That conversation happens at least once in every band that adds a horn. Here's why it happens, and how to get everyone speaking the same language.
What are concert pitch and written pitch?
Concert pitch is the sound you actually hear. Piano, guitar chords, bass and vocals usually talk in concert pitch. Press C on a piano and you hear concert C.
Written pitch is what's on the page for a transposing instrument. If a Bb trumpet part says D and the trumpet player plays that D, you hear concert C. There's a fixed distance between the page and the ear, and it depends on the instrument.
That's where the trouble starts in a band: the same note name can mean two different sounds. If you say "C" without saying whose C, someone's in the wrong key thirty seconds later.
Why do these instruments transpose at all?
To make life easier for the player. Instruments in the same family come in different sizes, and each size sits at a different pitch. Transposed parts let a player switch to another instrument in the family without relearning fingerings. On every saxophone, the same written note uses the same fingering. Move from alto to tenor and you don't learn a new system, only the sound changes.
The rest of the band pays for it, though. Whenever you talk about keys, somebody has to translate.
How much does each instrument transpose?
These are the ones you'll run into most in bands:
| Instrument | Key | Written C sounds as | Sounds, relative to written |
|---|---|---|---|
| Trumpet | Bb | Bb | A major second (whole step) lower |
| Clarinet | Bb | Bb | A major second lower |
| Soprano sax | Bb | Bb | A major second lower |
| Tenor sax | Bb | Bb | An octave plus a major second lower |
| Alto sax | Eb | Eb | A major sixth lower |
| Baritone sax | Eb | Eb | An octave plus a major sixth lower |
| French horn | F | F | A perfect fifth lower |
Guitar and bass technically sound an octave lower than written too. But the note name stays the same, so it never causes confusion in a band. The ones that do are the Bb, Eb and F instruments, where the note name changes.
Some instruments also come in other keys. Orchestras use C trumpets and A clarinets, for example. The ones in the chart are what you'll see most in bands, but it's still worth asking a new horn player what key their instrument is in.
How do you convert from concert pitch to written pitch?
The instrument sounds lower than written, so to convert, you go up:
- Bb instrument: a whole step above concert. Concert C is D for the trumpet player.
- Eb instrument: a major sixth above concert, or a minor third below, which lands on the same note name. Concert C is A for the alto player.
- F instrument: a perfect fifth above concert. Concert C is G for the horn player.
Chords move by the same distance. If the song is in concert G and the chords are G, Em, C, D, the Bb trumpet player reads A, F#m, D, E. The alto player reads E, C#m, A, B. Every chord moves the same amount, and the chord type stays the same.
Here are the common band keys, already worked out:
| Concert key | Bb instrument | Eb instrument | F instrument |
|---|---|---|---|
| C | D | A | G |
| D | E | B | A |
| Eb | F | C | Bb |
| F | G | D | C |
| G | A | E | D |
| Bb | C | G | F |
The chart shows something else too. Horn-heavy bands tend to pick concert keys like Bb, Eb and F, because they land on keys with fewer sharps and flats for Bb and Eb players. For guitar, it's usually the other way around.
What mix-ups happen most on stage?
- "Which C?" Talking about the key without saying concert or written.
- Handing the horn player the guitarist's chord chart. Chord symbols are in concert pitch. If a Bb trumpet player solos off that chart, they have to move every chord up a whole step in their head.
- Last-minute key changes. When the singer says "down a half step," the guitarist moves the capo and the bassist shifts the pattern, but the horn player has to translate the new key first. It's one extra step for them.
- Pointing out a note. "Play an E there" means a different sound depending on whether you said it to the trumpet or the sax.
- Forgetting the tenor sax octave. Tenor sax sounds an octave and a whole step below written. Copy a melody straight off the piano part and hand it to the tenor player, and it ends up in the wrong key and the wrong octave.
I cover how the singer picks the key, and how that decision spreads through the band, in the post on finding your vocal range. For horn players, the work usually starts right after that decision.
How should a band talk about keys?
Our rule is simple: in the band, keys are always said in concert pitch. "It's in Eb" means concert Eb. The horn player does the translating, because they know their instrument best. Chord charts have the concert key at the top. If someone writes a separate part for a horn, it gets labeled with the instrument too: "for Bb trumpet."
When a new horn player joins, ask two things before the first rehearsal: what instrument they play, and whether they read or play by ear. Ear players often do the translation without even thinking. Readers need a part written in the right key, or the first half hour of rehearsal goes on translating.
Same goes for pointing out a note or a section. "Come in on concert F" is always safer than "come in on F."
BandUp moves that translation into a personal layer. When a Bb trumpet player turns on personal transpose, the chords shift only on their own screen. The song's key and saved chords stay the same for everyone else, and the setting is saved on their account for every song. Live transpose in Stage Mode is a separate group layer: it changes the key on everyone's screen for the session, and the original key comes back afterwards.
To see from scratch how chords get moved to a new key, have a look at the transposing guide.