Tel: 0121 366 6216
Mob: 0796 636 7259

What’s the difference between overstrung and straight strung pianos ?

Posted on: July 3rd, 2017 by Graham No Comments

Overstrung and straight strung pianos

If you either own an older piano or are looking to buy one you are likely to come across some different types, so it may be helpful to understand some of the variations.

Below you can see an example of an over-strung … and its underdamped action

Example of an over-strung … and its underdamped action


Example of an over-strung … and its underdamped action


Below you can see an example of a straight-strung … and with its overdamped action

Straight strung piano


Straight strung piano with overdamped action.


In the photos are examples of a straight strung and an overstrung piano. As you can see the strings on the straight strung run vertically and perpendicular to the floor. In the overstrung the strings of one section gradually fan out towards the bottom left corner and bass section of strings are at an angle from the top left towards the bottom right of the piano. This crossing over of each section gives rise to the term ‘overstrung’. The advantage of the overstrung is that the bass strings can be as long as possible. Generally, a longer string will give a better quality of sound so the bass of an overstrung is usually richer and more resonant than a straight strung of similar size and age.

Strings, Tension & the Iron Frame

The ‘strings’ on a piano are actually made from steel wire. Throughout the treble section there are usually three strings for each note, and the reason for this is for volume; three strings will be louder than just one. As the notes progress lower into the bass section there are two strings for each note then just one for the lowest notes. The longer strings and larger hammers in the bass produce the necessary volume.

The number of strings on the piano varies from around 220 on an average upright to above 240 on a concert grand. With tensions on each string of around 75kg that adds up to around 15 – 20 tonnes. So why doesn’t it just implode under all that tension?
The answer is because the piano has a cast iron frame. The iron frame is the part in the photos painted a golden colour; it can be any colour but gold seems be the conventional one. The iron frame has great tensile strength and supports the tension of the strings. This ‘lump’ of iron is also why the piano is so heavy.

Comments are closed.