Develop the piano technique needed to create sounds layered over one another by de-constructing a polyphonic musical phrase into their individual voices and practising their tone production separately
Take a close look at the sequence of notes shown in Image 1 below. They are a sequence of chords in which I have marked the top notes as forte and the bottom notes as piano. Reversing them alternately as the sequence progresses. Practising as such is helpful in developing control over the production of tone. Becoming adept at invoking sounds at varying shades of tone ranging from pianissimo to fortissimo out of a couple of voices simultaneously affectively conjuring a polyphonic sound.
Polyphonic phrases often appear in compositions. A musical phrase is considered polyphonic when it has more than 2 voices at the same time. Phrases with only a single voice are termed monophonic while those with 2 voices are homophonic.
Obvious when compared to a monophonic phrase, polyphonic phrases have added layers in the sounds they produce. Enriching the listening experience with added flavor. For example, were the voices present in the phrase shown in Image 2 below, played separately the melody would still be recognizable, combined they bestow a much more gratifying listening experience.
To appreciate how polyphonic phrases transform the listening experience always de-contruct them in practise by practising each of the voices separately. This also teaches the piano student about the structure of the music in the phrase.
Once de-constructed the difference in the rhythm between the voices is noticeable. The first priority is to absorb them through practise. Then begin the process of coaxing the tone out of each voice at varying degrees ranging from pianissimo to forte. This can be accomplished by adjusting the touch of the fingers as they make contact with the keys of the piano. Strong and heavy touch for a loud tone and light and delicate touch for a soft tone. While keeping the wrists supple making sure they do not lock-up.
When able to produce tone as such, you shall be able to layer the different tone from the different voices occupying a polyphonic musical phrase, as a result produce a textured sound.
After being able to dominate the tone production summoning piano or forte at will, raise the level of your mastery of the musicality of the phrase by practising them first at a slow tempo, then moderate and fast. Having done so, increase it up a notch by alternately practising one voice legato and the other staccato. Indeed challenging but through persistent practise the result is a web of polyphonic phrase produced with refined texture and plasticity.
If you find yourself struggling to accomplish the tasks described above, practise in small sections such as a bar or like I do half a bar when I feel overwhelmed, then build upon the small successes until a complete phrase is rendered properly. Let the compound effect take place through accumulated small progress. Stay with a consistent fingering combination when practising those small sections to maintain stability in execution.
It is a long list of things that need to be done, even then it is not enough unless the process is repeated until security is achieved in the fingers especially and all motions involved in general. Another benefit of repetition is you gain clarity in the brain because as you make your way through a phrase you are forced to think about the notes in it, an understanding about their pitch, tone, tempo and relationship with the other notes around them begin to develop and gets stronger as they are played several times. Emphasis should be given to practising as such when learning polyphonic phrases because of the layers of different voices present within them.