I love this passage from Sonny's recording with Monk. But as I transcribed it, a few things really stood out to me.
Download the PDF Transcription: I Want To Be Happy.pdf
First, rhythmically this is super Bebop-ey. A long string of 8th notes, broken up by some triplet and 16th note turns for variety. You can learn a lot about the language of bebop just by scatting this rhythm along with the recording.
In terms of notes, its surprisingly simple. The notes are almost entirely chord tones or neighbor tones from the relevant scale. Thats a sharp contrast from all the chromatic sounds of Bebop.
That is, except for beats 3 and 4 on the Bb7 chord where he plays: Gb, Db, Cb and Ab... But, if you spell those same pitches with sharps instead you get F#, C#, B and G#, which is basically B minor.
Why is this noteworthy? Because the notes of the B melodic minor scale, where these notes comes from, has another name if you play it from Bb to Bb: "Bb Altered Scale."
(For the nerds: The altered scale is the 7th mode of melodic minor)
Sonny then shifts that same line down in the next measure to resolve it over Eb. A nice little tension and release melodic motif.
This is a little move I've been seeing a lot in Sonny's playing. Where he plays simple notes, like chord tones and scale notes, then during a big dominant chord moment he uses a more outside sound like the Altered Scale, a Tritone Substitution or even just a side slip.
When I hear this, it really makes that dominant chord stand out and create a lot of extra tension.
Let's put this sound into practice this week.