Others may find this mystifying as well...a tune has
1) a key signature (sharps & flats at the beginning of the song),
2) the chord & note symbols that appear on the lead sheet,
3) a concert key sound (the pitches that the listener hears), and
4) my instrument may not be tuned to C.
is there a tutorial on how to understand how BB can be used to modify these parameters...or maybe an article somewhere?

I don't think I would use #2 as a definition of "key", unless you mean using chords, melody and harmony to determine a key signature. But --

For #1, how it works depends on which version of BIAB you have. If it's 2015, there is an icon for key in the upper center of the screen. It presents two nifty sliders, to transpose when changing the key signature (left-hand column), or not (right-hand column). Older BIAB versions just work like the left-hand column does now.

Transposing instruments (trumpet, sax, etc.) are handled in one of at least two ways (that I know about), to deal with your #3 and #4. Preferences, Display, Transpose Options is the one I use. The song plays in concert key and displays notation in the key needed for the transposing instrument, so both can sound correct when played together.

I recommend not using Preferences, Transpose because you can forget you did it. I think there are a few other ways to transpose but I don't use them.

Did that help?

When someone tells me what key a song is in, I expect them to tell me concert key.

If they tell me Bb and I have the tenor sax in my hand, I know it's C. If I have the alto in my hand, I know it's G.

The chords in the song are definitely related to the key, and sometimes in a song there is an implied key change (not noted in the key signature); the chords and/or accidentals in the notation will either give you a clue or outright tell you.

Matt gave you the advice on how to transpose the display for your instrument.

However, I've been to a lot of jam sessions, especially jazz jams where they put a concert chart in front of you. I predominantly play tenor (Bb instrument) so I have to sight transpose by adding 2 sharps (or subtracting 2 flats) and playing everything a whole step higher.

I can't sight-transpose on the Eb alto, but if it was my primary sax, I'd learn that one too.

If you don't play a C instrument, this is a very useful skill to acquire. You don't have to do it in a day or two, but try a little at a time, with simple songs first, and after a while it gets to feel comfortable.

Insights and incites by Notes

Even if you play a C instrument this is a useful skill. Just imagine, somebody gives you some sheet music and the singer says: "That's a third to high."

No, the singer is a "third too flat"

Larry

or definition 5) That which unlocks the sound.

Some people have incredible transposition skills.

As a multi-instrumentalist, transposing on the guitar is easy, piano, sax and others very difficult as you have to use a completely different fingering pattern in each key.

And being a musician is a collection of skills, we don't all have equal amounts of all, so transposition alone doesn't define whether you are a good musician or not.

I played with a pianist that was simply and adequate soloist. He really didn't improvise above the very basic level. He comped well, he sightread well, and could transpose anything.

For example, many standards are written and usually played in Bb or Eb. Take an Eb standard like "Misty". If a singer came in and said, "Can you do this in A?" (or any other key) he could play it just as well as in the standard key. I was amazed by this guy. Bass lines, comp parts, countermelodies, everything, equal in any key you called.

It's a special skill. One I don't own. I can do simple transpositions in my head on the sax, but say, "Can you take it up a diminished fifth" would leave me playing the most rudimentary parts, if at all (depending on the difficulty of the song).

When I first learned guitar it was (and still is) fun to transpose. Same fingering, same everything, but starting on a different fret. Change the key? Sure. Want to go up a half step for the last verse? Wanna do that again? (on the other hand, reading music on guitar is more difficult).

Sorry to hijack the thread and go off on a tangent.

Insights and incites by Notes