Y'all may recall that I am switching to bass after 50 years of playing rhythm and lead. I've been practicing scales (fundamentals,son, fundamentals). My question now is about transposing. If a song is in the key of A, on a 6string I know my root is either 5th fret on the bottom string or open 2nd string. Where does this translate on the bass? Is there a standard formula, such as A on treble = G(?) om bass.
Others have answered, but I'll try to summarise.
(Usually) The 4 strings of a bass are tuned to the same pitches as the lowest 4 strings of a guitar: EADG - only an octave lower. So 'A' is in exactly the same place on the bass as it is on the 4 lowest pitched strings of your 6-string guitar, only it sounds an octave deeper.
Don't be confused by the fact that bass music is
written using a different 'clef'*. If you want to
read bass music, Major Softie has given you a good diagram showing you how pitches are written using the bass clef. But remember that even though bass notes are written on a different line or space to notes written for (treble clef) guitar, an 'A' played on the the 5th fret of the E (bottom) string on a bass is the same 'A' played in the same place on a guitar, only it sounds an octave lower/deeper (and the same goes for all other notes).
Long summary, huh? Repetitive, too! I Hope it helps.
*Clef is French for 'key', but it doesn't have anything to do with changing from one key to another (as in "I can't sing this, it's too high for me. Let's change key"). In music theory, transposing means changing key. There's no transposing involved in transferring from a guitar to a bass that's standardly tuned.