Over time, due to changes in temperature, humidity, and string tension, a piano's pitch can drop, causing it to sound out of tune. Pitch raising is necessary to bring the piano back to the correct pitch level (concert pitch A 440) before fine-tuning it.
Here's a general outline of the pitch-raising process:
1. Inspection: Before starting the process, the piano tuner inspects the piano for any visible issues or damages (especially loose tuning pins) that could affect the tuning process. Structural problems or damaged components are addressed before proceeding. However, loose tuning pins are usually NOT addressed, and the piano is usually deemed to be un-tunable. 2. Initial Assessment: The piano tuner measures the piano's current pitch using an electronic tuning device. Standard pitch for most pianos is A4 = 440 Hz (A above middle C) If the piano's overall pitch is significantly lower than this, pitch raising is necessary. 3. Apply Pitch Raise: The actual pitch raise involves bringing the piano's pitch above A 440. This process is typically begun using an electronic tuning device. A rough tuning is usually performed on this first tuning, and then a subsequent tuning or fine-tuning is later applied. 4. Stabilize and Settle: After the first rough tuning (pitch raising), some piano tuners let the piano sit for several weeks to allow the strings to settle and stabilize at the new tension. Some piano tuners perform a pitch raising and a fine tuning during the same visit. 5. Fine-tuning: Once the piano has stabilized, a piano tuner should proceed with fine-tuning. Fine-tuning involves adjusting each string to its correct and precise pitch using a piano tuning lever and a tuning device or tuning aurally (by ear). This process requires careful attention and skill to ensure the piano sounds harmonious and is in tune with itself. 6. Testing: The piano tuner, and sometimes the customer, play songs or various chords and intervals across the piano spectrum to ensure that it sounds consistent and in tune throughout the entire range.
Please note that pitch raising and fine-tuning a piano is a delicate and precise task that requires experience, skill and knowledge. It is best performed by a professional piano tuner who is familiar with the process and has the necessary tools and expertise to do the job correctly and without damage to the piano. Additionally, pitch raising should only be attempted if the piano's pitch has significantly dropped below A 440, and it is not recommended or necessary for annual routine tuning maintenance.