As your Piano Tuner Wilmington DE , I am frequently asked why a piano needs a “pitch raise.” The following is an explanation in order to correct any confusion on the issue.
A piano has over two hundred piano strings, each with a tension around 150 lbs. That totals around 30,000 lbs. of total tension, which a wooden structure cannot maintain indefinitely. If a piano has been tuned within the past year, it typically drops in tension enough that the pitch of a key will drop 2-5% of the way to the next note below. In pianos, the term “cents” is used instead of “percent”, so a piano which was tuned in the previous year, will be termed 2-5 cents below standard pitch. Standard pitch is an agreed-upon pitch so that all instruments can be played together.
When the pitch of a piano is raised during a tuning, the entire instrument flexes to accommodate the new overall tension. As a result, for every amount the pitch on a string is raised, it will fall 10-38% of the raised amount in the next ten minutes. That amount of pitch that it falls is not significant if the piano was only 2-5 cents low at the beginning. If, however, the piano had not been tuned for several years and the pitch was 10 – 20 cents low, then there is a problem. If such a piano were tuned to standard pitch, then it would be out of tune by the time the tuning is finished.
In such a situation, the piano tuner must perform a “pitch raise”. This requires rough tuning of the piano 10-38% too high, then fine tuning the piano afterwards. This requires more than twice as much work as a normal piano tuning, because the rough tuning requires significant effort to raise the pitch of the strings back to their original tension.
You may wonder why the piano cannot be accurately tuned one time through, simply by tuning the piano a set amount too high. The answer is that different parts of the piano flex different amounts. The bass section typically falls 10-15%, the tenor section 19-29%, and the treble section 25-38%. Additionally, every piano design flexes different amounts in each section, so the amount of flexion cannot be accurately predicted.
It is much easier to simply tune the piano at least once a year, rather than needing to correct for years of neglect of the instrument.
If you have any questions about your piano, please ask us. We are your Wilmington DE piano tuning experts. We also proudly provided piano services in the areas of Philadelphia, Eastern Shore Maryland and Southern New Jersey.