Study Brahms’s Waltz in A flat, Op. 39 No. 15. The right hand sings in sixths and thirds (C over E flat, A flat over C in bar 1) over the left hand’s waltz bass and chords. Hold the pedal through each bar’s harmony and lift it only part of the way where the melody’s passing notes would blur: a half pedal clears the top and keeps the bass. The double-notes card shows how to keep the sixths even and joined. At the keyboard: change pedal depth while holding a chord.