Just listen to Shaye in the first two seconds of this video:
Before the song starts, she runs up an arpeggio through these notes (I'm giving Concert Pitch): Bb - Eb - G - Bb - C - Eb.
They make up the chord of Eb, or more accurately Eb6.
Why does she do this? I can think of two reasons.
(1) She is signalling to the rest of the band that this song is to be played in the Key of Eb.
(2) She is establishing in her own her head the 'feel' of the key in which they are about to play. This could be particularly important if the previous song was, for example, in the key of F, and she wants to clear her head of that key and firmly establish the new one.
I have noticed this is a procedure Shaye follows in starting many tunes. This is in addition to the great care she takes to get the tempo just right - sometimes tapping her foot for quite a while before counting the band in with 'One, Two; One, Two Three, Four'.
It seems a good idea and I wonder whether there are many other band-leaders who adopt it.
