How Much Tension Is On Piano Strings

How Much Tension Is On Piano Strings? Piano String Tension

How much tension on piano strings? How important are the piano tension strings? What are the advantages of having higher-tensioned strings on your acoustic piano? If you are curious about how much tension there is on your acoustic piano, join us, as we are going to give you some insights on how pianos and their strings work.

How Much Tension On Piano Strings

So, how much tension on piano strings? Before we answer that, let us go first about how a piano produces its sound. As you already know that the strings are the main reason why this musical instrument is able to produce its sound; you should also know that these strings are tightly stretched over the piano’s cast-iron frame. When these strings are struck by the piano’s hammers, they are able to vibrate, resulting in them producing a sound.

In a typical piano setup, the piano’s high-treble strings are the thinnest, with an estimated about 0.7mm of thickness, and their gauge and length constantly increase as the pitch goes lower. The shorter-treble piano strings are less resonant compared to the longer ones, which is why manufacturers use unison strings to be able to get a louder sound from these shorter strings. These unison strings are composed of two or three piano strings that are tuned to the same pitch.

Usually, the treble pitches tend to have three unison strings; the tenor pitches use two unison strings, while the bass range uses only one string. This results in 88 notes and can reach up to a total of 236 piano strings. So, how much tension on piano strings really is there? In most cases, each of the piano strings has a tension of 160 to 200 pounds, which in total is about 38,000 pounds of string tension in an acoustic piano. That is how much piano string tension there is in one.

This is the reason why modern piano manufacturers use cast-iron frames and a solid back frame instead of wooden frames, as it is able to withstand the heavy amount of pressure that comes from it.

Reasons For Acoustic Pianos Having High-Tension Strings

Reason 1:

When it comes to playing acoustic pianos, there is a much-needed higher amount of energy to make the strings vibrate at a higher tension, and with this setup, you can get a better sound from the musical instrument, as the strings are able to transfer more energy to the piano’s soundboard and bridge, resulting in a more powerful and louder sound from the acoustic piano. This is also the main reason why piano manufacturers opted for more substantial felt hammers instead of small-leather covered hammers.

Reason 2: 

Another reason why piano strings have a higher tension is that these strings undergo more complex vibrations, which results in them delivering a brighter and fuller sound compared to piano strings with lighter tensions. In the old days, acoustic pianos tended to sound like harpsichords, where the difference was that the older version of hammers allowed more control over the piano’s volume through the strength of the blow on the musical instrument.

So, if you are familiar with the timbre of most acoustic pianos today, this is associated with the increase in string tension starting from the 19th century onwards.

Reason 3: 

The third reason why it is better to have higher-tension piano strings rather than a lower-tension version is that the pitch of these strings tends to be more thermally stable at higher tensions compared to the opposite ones. When there are always sudden and frequent changes in temperature and moisture, acoustic pianos tend to change in pitch more evenly with similar tensions, giving a more even spread of tension on the piano’s pins and frame. 

So, with higher-tension strings, it is rare for it to happen compared to the old days when pianos had wooden frames and lighter-tension strings.

Advantages Of Lower-Tension Piano Strings On Your Acoustic Pianos

In the old days, pianos only came with lower-tension strings to accommodate the heavy stress that is put on the wooden frame of the acoustic piano. However, as time went by, more and more people started to like higher-tension piano strings, which also resulted in piano manufacturers to also change the wooden frames into cast-iron frames and more solid ones.

Although there are disadvantages to having lower-tension piano strings, there are also some advantages in having it on your acoustic pianos, and one of them is there is less stress on the piano’s pin block, which can also mean that it can last longer compared to using higher-tension piano strings that can apply some heavy pressure to it.

One also of the main reasons why pianos can no longer be tuned is because of pin block failure, and using lower-tension piano strings allow it to have a lesser chance of happening compared to higher-tensioned piano strings.

The second reason is that when there is less pressure on the block pins when tuning, they tend to easily slide into their place without having to slide out, which is pretty usual when it comes to higher-tensioned piano strings. When block pins are also under pressure, they usually skip out of their place, making them harder to put in their proper spot, which forces the piano tuner to overstretch the piano strings just for him to find the sweet spot.

You will notice that when a piano technician is tuning your piano, you can hear the block pins are also skipping, and with the usual overstretching, it can shorten the lifespan of the piano strings, which can also possibly shorten the life of the acoustic piano.

So, how much tension on piano strings? Each of the strings usually has a tension of about 160 to 200 pounds, and in a typical concert piano, there can be about 236 strings on it, so it can add up to almost 38,000 pounds of tension, depending on the size of the acoustic piano, as there are also much smaller ones.