Is a series of steps of about 15 different steps taken to correct, soften, harden, reshape, alter the weight, the density and the resilience of the hammers in order to affect and correct the sound colors, the evenness, the sustain, the volume and the attack. There are also additional voicing steps taken on string termination points, on duplex scale, on capo bars, on string levelling and string matching with hammers.
Voicing was always considered a “master” job with voicers having top salaries in piano factories. A good voicing can transform a piano bringing out its best and a bad voicing can downgrade an otherwise excellent instrument.
Within limits, voicing can give us a choice between an introvert, softer and mellower sound and a more extravert, open, transparent and projective sound. Piano hammer is like a basketball: if voicing techniques could apply, they would affect the air pressure, the weight, the texture, the curvature, the elasticity and the bounce time of the ball.
Moisture variations cause resilience loss, millions of string strikes harden the hammer tip and reduce weight, microorganisms and neglect affect evenness and so on, commanding a recurrent voicing program that normally is in parallel with tuning.