Understanding the crucial pre-tuning process for neglected pianos.
When a piano is neglected for several years, the overall tension of the strings drops significantly, and the pitch falls well below the standard A440 Hz. If a tuner tries to pull the strings straight up to pitch in one pass, the immense added tension will cause the soundboard to flex, instantly throwing the first strings tuned out of tune again. A 'pitch raise' is a rough, high-speed pre-tuning process that safely adds the required tension across the entire frame before the fine tuning begins.
An acoustic piano has over 200 strings holding approximately 18 to 20 tons of combined tension. If a piano is 50 cents flat (a quarter of a tone), pulling one string up to A440 adds an enormous amount of pressure to the cast-iron plate and the wooden soundboard. As you move from the bass section to the treble, that compounding pressure forces the soundboard to bow slightly. By the time you finish tuning the high notes, the middle section you just tuned has sagged flat again.
A pitch raise (sometimes called a pitch correction) solves this physics problem. The technician moves rapidly through the piano, pulling every string slightly sharp of the target pitch. They intentionally overshoot the note, knowing that as the rest of the piano is tightened, the added tension will cause the initial strings to drop right back down to roughly A440. It is a calculated over-compensation.
If your piano has not been tuned in over two years, it almost certainly requires a pitch raise. A standard fine tuning is impossible if the pitch has drifted more than a few cents. Our expert technicians at Piano Inside will always assess the piano's pitch before beginning work and explain exactly what is required to restore your instrument to concert pitch.