Pitch is a very important consideration when it comes to tuning a piano. When a piano’s pitch deviates from the standard, a pitch correction must be performed before the piano can be fine tuned.

But what exactly is a pitch correction and why is it needed?

Before we can answer these questions, we first need to cover some basic information about pitch. What is this thing that we call pitch?

Audible sound consists of waves whose frequency can be measured in cycles per second, or hertz. The higher the hertz value (cycles per second), the higher the pitch of the sound that we hear. Doubling the hertz value of a sound will generate a sound exactly one octave higher. For example, a sound that vibrates at 220 cycles per second is an octave lower than one that vibrates at 440 cycles per second.

You may have heard a piano tuner refer to something he or she called “A-440.” Some piano tuner-technicians even include this term in the name of their business. I remember back in the early years when my dad ran our family business, it was “Domeny’s A-440 Piano Service.”

But what does “A-440” refer to? Very simply, it means that the note A above middle C is tuned to a frequency of exactly 440 cycles per second. Although there are exceptions (for example, many orchestras tune to A-442), A-440 is the international standard for pitch when it comes to the piano.

Well, that’s the standard. That’s where your piano should be – where it needs to be – in terms of pitch. But obviously just because your piano should be at A-440 doesn’t necessarily mean it is.

There are two main reasons why a piano’s pitch may deviate from this standard.

The first and perhaps most obvious reason is neglect. Piano wire, though composed of steel, is highly elastic and stretches when placed under tension. The longer a piano sits between tunings, the more of this stretching that takes place. And because lower string tensions means lower pitch levels, the more the strings are allowed the stretch, the more the pitch of the piano will drop. It is not uncommon for a piano that has been neglected for 15 or 20 years to be at A-415 instead of A-440, which is a full note flat. In other words, when you play the note Middle C, what you’re actually hearing is the note B directly below Middle C.

The second reason why a piano may deviate from the pitch standard of A-440 is that a piano’s pitch fluctuates with changes in relative humidity. When humidity increases, the piano’s pitch rises. Likewise, when humidity decreases, the piano’s pitch drops. For a discussion of this phenomenon and why it occurs, please refer to my blog post titled “What Causes a piano to Go Out of Tune?” and especially reason #2, Temperature and Humidity Changes.

This means that even a piano that is serviced on a regular schedule may occasionally deviate sufficiently from the standard of A-440 that pitch will need to be corrected.

Okay, now we’re ready to tackle the question, “What is a pitch correction?” Put simply, a pitch correction is a very fast, rough tuning that brings the piano back to the proper pitch level. If the piano’s pitch is low (flat), we raise it. If the piano’s pitch is high (sharp), we lower it. In a pitch correction, larger changes are made to the strings and tuning pins than can be made in a fine tuning. Once completed, a pitch correction is immediately followed up with a fine tuning.

Except for these essential differences (fast; imprecise; larger movement of strings and tuning pins), the process of performing a pitch correction is essentially the same as that used for a fine tuning.

Because precision is not an issue when a pitch correction is being performed, a pitch correction can be completed in about one-third to one-fourth of the time that it would normally take to complete a fine tuning. Most piano tuner-technicians take this fact into consideration when setting their price structure. Generally speaking, a pitch correction will be priced at about 25% to 33% of the cost of a fine tuning.

So, to summarize what we’ve covered thus far: When a piano’s pitch deviates from the international standard of A-440, a pitch correction is performed. A pitch correction is a very fast, imprecise tuning in which larger movements of the strings and tuning pins are made. A pitch correction, once completed, is immediately followed up with a fine tuning in which only small changes are made.

Please note that we have delineated two separate and distinct steps for tuning a piano when pitch needs to be brought back to the international standard of A-440: First comes the pitch correction. Once this is completed, only then can the piano be fine tuned.

Now, this brings us to an interesting question that many ask at this point: Why must this be done in two separate steps – pitch correction, then fine tuning? Why can’t we pitch correct and fine tune a piano simultaneously, in one big, single step?

The answer to this questions lies in something that I have alluded to in a previous blog post. It is the principle that the smaller the changes that are made to the strings and tuning pins, the more stable the tuning will be. Of course, the opposite is also true: The bigger the changes that are made, the less stable the tuning will be.

The reason for this is actually not that difficult to understand. A piano’s plate (the large metal “harp” that is usually painted gold – an essential part of the load-bearing structure of the piano), although made of cast iron, is still surprisingly flexible. Tightening one string by a large amount will cause the plate to flex slightly in the area near that string, which in turn will cause neighboring strings to lose tension and drop in pitch. Now, if those neighboring strings have already been precisely tuned, guess what just happened to the precise tuning of those strings? Suddenly they’re not so precise anymore!

Simply put, this means that a fine tuning will not be very “fine” if large movements are made. Or to put it another way, it is impossible to perform a fine tuning when large pitch changes are needed. A pitch correction allows for those large changes. And although imprecise, a properly executed pitch correction will put each string close enough to its final position that only small changes will be needed in the fine tuning.

So the next time your piano tuner-technician tells you that your piano needs a pitch correction, please understand that this means that larger pitch changes are needed than can be accomplished with a fine tuning alone. Given the fact that a pitch correction is not expensive (my clients pay only about $30 for a standard pitch correction), the final result – a better, more accurate, more stable tuning – is well worth the added expense.

If you live in the Inland Empire area of Southern California and are in need of piano service, I would love to hear from you! Feel free to call me directly at (909) 824-2561; or you can contact me using this online form.