Sometimes when we go out to tune an old piano we have the conversation with a customer as to whether the instrument can be tuned at A4=440Hz, which is standard concert pitch. Read more to find out what circumstances mean we recommend tuning a piano under pitch.
When was the piano made?
Standard pitch is generally agreed to mean that the A above middle C, (A4) sounds at 440Hz per second. However this was not always the case. Although exact dates vary it is generally agreed that pianos made before1920 might have been made with the tension being lower than modern pianos, for example A4 - 437Hz. This being said this is not the only determinate factor and does not mean that this piano doesn't have the capability to be tuned at A440Hz.
What style is the frame? What style is the stringing?
The second factor which affects whether a piano can be tuned at standard pitch is what style of frame it has. There are generally two types of upright piano frame, the full frame and the half frame. A full frame will be one solid piece from top to bottom which is cast all at the same time. It has a very high structural integrity. The second type of frame, usually in older pianos, is made in two parts with the top section covering the pins, separate to the bottom section which holds the pins on the hitch pin. This type of half frame does not have as much integrity as it is built in two sections and the two do not attach to each other.
When considering the pitch at which a piano is tuned the style of the frame should be taken in to consideration as half frames might be an indication of a lower pitch.
The frame is also linked to the stringing style of the piano. Modern pianos are cross strung which means that the bass strings are on an angle and go over the top of the treble steel strings. However on older pianos the style might be straight strung which means all of the strings go in a straight line down to the bottom of the piano. Some straight strung pianos were made to be below standard pitch so it is important to consider this factor.
What condition are the strings, pins and wrest plank in? What is the current pitch?
After considering the frame and stringing style of the piano, it is important to consider the condition of the strings, pins and the wrest planks. As a piano ages it gains a certain amount of dirt and grime which is to be expected; some pianos gain some rusting on the strings and the pins from environments which are not ideal e.g. a little damp. In these cases you need to be very cautious about moving the pitch of the piano too far in any one direction as the strings are significantly more prone to snapping. The pins in the wrest plank might also be a little soft or even loose from age in which case moving the piano to pitch probably wouldn't hold anyway.
In conjunction with this what pitch is the piano currently at? If the pitch is only a little low e.g. 438Hz the piano will probably hold being pulled back to 440Hz. If however it is below 435Hz the likelihood of a string snapping on a good condition piano is amplified; but on a piano with rust the risk goes up exponentially. This can also be a very expensive fix if lots of steel strings snap and need replacing, or a copper bass string which is more expensive.
What type of action does it have?
Upright pianos have two different type of action, the older version being the over damper action. This action has the damper system on top of the hammers with a rail above, whereas the modern upright piano action have the dampers underneath the hammers out of sight. If a piano has an over damper action it is important to consider its pitch as some of these instruments were made to be under what is now considered standard pitch.
Easy does it, or one swift movement?
After considering all of the above factors you might have decided that the right thing to do is to pull the pitch of the piano back up to A4 = 440Hz. When doing this there are two techniques. One is that you over pull the pitch to above 440Hz increasing the tension rapidly so that it drops back down to 440Hz for retuning. The other method is that you pull the piano up incrementally over time so that the tension of the piano increases at a slower rate.
Both methods have their merits and it is a judgement call on which to use depending on all of the factors above.
We hope that you have enjoyed this blog Piano Tuning Series: Can My Piano Be Tuned to Standard 440Hz? and that it has helped your understanding on the factors to consider when tuning a piano to standard pitch.
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