Why Do a Separate Pitch Raise When Tuning a Piano?
If it has been awhile since your last piano tuning, then your piano tuner/technician will likely recommend a pitch raise in addition to the tuning. This can be frustrating as it adds time and often cost to the piano tuning visit.
This article will explain what the pitch raise is and why it must be done.
Table of Contents
What is a Pitch Raise?
Why Not Just Start With a Fine Tuning?
Why Use Double Pass Piano Tuning?
Conclusion
What is a Pitch Raise?
A pitch raise is done when a piano is significantly lower than the standard A440 tuning. The process can be explained simply: every note on the piano is raised to slightly above the standard tuning.
The amount above the correct tuning is proportional to the how far below pitch the piano started.
The idea is to get the piano roughly in tune before doing a standard fine tuning. We’ll see why this is necessary in the next section.
Why Not Just Start With Fine Tuning?
This section is going to be technical, but it will show you that this is really a necessary step to produce a good tuning that is stable all the way until your next piano tuning.
Suppose you put a string perfectly in tune and the two strings next to it are significantly below pitch:
Now imagine you bring those two strings up to pitch. Raising the pitch on a stringed instrument means increasing the tension of the string.
This tension exerts a force inward on many parts of the piano including the bridge, the plate, and the pin block:
If you think about what happens when you hold a string in front of you taught and then pull your hands together. The string will slacken and droop.
This is exactly what happens with the indicated middle string.
So if you spend a lot of time and effort getting that middle string in tune, and then you raise the pitch of the surrounding strings, that string will actually fall below pitch.
This is why a pitch raise pulls all the notes above the correct pitch—not to exactly in tune. As you perform a pitch raise across the entire piano, these notes that were too high will drop down to be close to being in tune.
This is also why you cannot fine tune piano that is significantly below pitch without first doing a pitch raise.
All the effort of the earlier fine tuning will be wasted because tuning other parts of the piano will affect that tuning.
Why Use Double Pass Piano Tuning?
This is also why I, at Bear Hill Piano Services, use double pass piano tuning as a standard practice on all pianos. Almost every piano will start below pitch.
There are several reasons why a piano may develop pitch issues over time. One common cause is changes in temperature and humidity, which can cause the wooden components of the piano to expand or contract.
This can cause the tension on the strings to change, which in turn affects the pitch. Other factors that can contribute to pitch issues include changes in string tension, wear and tear on the piano's components, normal use, and improper tuning techniques.
The physics explained above applies even to pianos that are fairly close to pitch.
By always doing two passes on a piano, I am able to first bring the piano up to pitch and then accurately fine tune. This means I do not have to charge extra for a pitch raise.
It also ensures that the piano stays in tune during the fine tuning and is stable after I leave.
Conclusion
Regular piano tuning can help ensure your piano will not need a pitch raise when the tuner shows up. This article shows what a piano pitch raise is and why it must be done sometimes.
A piano pitch raise is a specialized procedure that is necessary when a piano's pitch has fallen significantly below the correct level.
Regular maintenance and tuning can help prevent the need for frequent pitch raises and keep your piano sounding beautiful for years to come.