Sometimes you need to play quieter chords for some registrations on electronic digital keyboards so that loud chords do not drown out notes of the melody. Many keyboards have only one volume control for all keys, bass and treble. They do not have hammer-action keys which can be played softer or louder. So you must play softer with the left hand.
You can play chords softer by shortening them to 1/4 or 1/8th duration and playing them only once or twice to the measure. Then you can play some louder chords of 1/2 or full measure duration to fill in pauses or silences in the melody. Louder or longer chords can also be played in improvised measures added to the end of phrases in the melody.
So you play chords of shorter duration and less often while the melody is being played, and fill in with chords of longer during during pauses in the melody, during silences or rests and empty measures.
You can also soften chords by playing only two of their notes instead of three or four, or by playing only one note instead.
Playing chords with the left hand on deeper keys below note middle C and the melody with the right hand on notes higher than middle C, helps to separate the harmony from the melody and to stop chords from smothering the melody.
A quality keyboard should have separate volume controls for bass and treble octaves or for each different octave. Then it could be adjusted more like a manual piano can be adjusted during tuning.
