Pitch-raising up is a technique used to “overcorrect” pianos. For example, a piano that has fallen to A=435Hz needs to be tuned to A=440Hz to achieve the desired A=440Hz. Instead of simply tuning it to 440Hz, it needs to be overcorrected and tuned to 441.57Hz. After some restoring, it will approach 440Hz.
Pianos have 88 notes and over 220 strings. Pitch-raising up takes time; this is what’s commonly referred to as “coarse tuning” and “fine tuning.” Pitch-raising up is like coarse tuning, while the simultaneous tuning and testing are like fine tuning.
New York Piano Tuner : I used ear tuning (also known as auditory tuning) and state-of-the-art software-based electronic tuning equipment for sound tuning. (The frequency for home concert tuning is 442 Hz.) 我采用耳调音法（也称听觉调音法）和最先进的基于软件的电子调音设备进行调音。（家用音乐会调音的频率为 442 Hz） Chen YN 调音主页
New York Piano Tuner : I used ear tuning (also known as auditory tuning) and state-of-the-art software-based electronic tuning equipment for sound tuning. (The frequency for home concert tuning is 442 Hz.) 我采用耳调音法（也称听觉调音法）和最先进的基于软件的电子调音设备进行调音。（家用音乐会调音的频率为 442 Hz） Chen YN 调音主页 