What does Straightstrung and Overstrung mean on an upright piano?

When it comes to upright pianos, particularly when looking at older models or for those who are looking to sell an old second hand piano, one of the first questions that any retailer will ask after the manufacturer is ‘Is the piano over or straight strung” or “Is it over or underdamped?”

Following our guide to buying a second hand piano, we thought we’d explain some of the things to look out for when buying a piano.

The ways in which the strings are laid in a piano may sound simple, however they have a dramatic impact on the quality, durability and overall sound of the piano. Today we’ll be exploring the differences between the two and how they impact the value or lifetime of your piano.

What is straight strung and Overstrung?

There are many intricate and delicate parts of an upright piano and in order to maximise use of space, two main methods of stringing the instrument have historically been used.

The first is ‘straight strung’. As you might expect, this is the process of literally stringing an upright piano in a straight manner. The strings run vertically and parallel to each other from the top to the bottom in a straight line. Meanwhile, overstrung pianos (or cross strung pianos) instead position the bass strings over the tenor strings in what almost looks like an ‘x’ shape. These strings run in a more diagonal direction and cross over one another.

Which is preferred?

When it comes to upright pianos, due to their more compact size, length of string is a key factor in what gives the instrument its strength, power and rich tone. As they travel diagonally across the instrument, overstrung pianos are vastly superior to straight strung instruments as they allow for far more string length, however certain straight strung models can still be good instruments (For example the C.Bechstein model 10) but this is rare and most straight strung instruments unfortunately have no retail value.

Almost all newly built pianos use overstringing for this reason as it allows not only a better position of the bridge, but also allows the frame design to be more secure, solid and durable.

A W.Hoffman overstrung piano

In terms of sound production and quality, having the bridge (that helps transmit vibrations from the string to the soundboard) more towards the centre of the piano makes the instrument’s tone far purer and more efficient. If you compare an overstrung and a straight strung piano side by side, the straight will often feel more ‘tinny’ and less ‘full’ than the overstrung piano.

Another reason overstrung is preferred is because of the increased string length and added tension, cast iron frames are required to hold the instrument together (else it would collapse under its own tension). This combined with added braces in the back of the piano also helps keep the piano in tune at a more stable level (depending on where it is kept.)

Overdamped Vs Underdamped Actions

Much like straight vs overstrung, the positioning of the dampers on an upright piano is also incredibly important when either buying a second hand instrument or selling one.

The easiest way of identifying which kind of damper your piano uses is to lift the lid of the piano. If you see a wooden bar with the hammers sitting below, it is overdamped. On an underdamped piano, when you lift the lid, you will have an unobstructed view of the hammers with felt dampers sitting below.

An old overdamped piano (note the wooden bar above the dampers)

Damping matters because it is the delicate mechanism that a piano requires to stop notes ringing on once you lift your finger from the key. Tools such as sustain pedals work in harmony with the dampers to allow strings to continue to ring once keys are lifted.

A modern underdamped piano

But what is the difference between a piano that is overdamped and one that is underdamped?

The key difference between the two is that with overdamped pianos, the damping rail is found above the hammers. As the dampers are positioned near the top end of the string, the damping effect is less effective.

This is why almost all new pianos are built with underdamped strings as standard. The damper felts on an underdamped piano are beneath the hammers. This means that because the damper is further towards the centre of the string, it is able to stop the vibration almost instantly as the finger is removed from the key, resulting in a much clearer definition of sound as the surrounding strings will not be vibrating once the key is lifted.

In short, the best combination of a piano is for the instrument to be overstrung and underdamped.

This not only gives the strings more opportunity to resonate and create a richer, deeper sound, but also allows for more precise playing with added definition to your play thanks to highly responsive dampers. 

What do I do with an instrument that is not overstrung and underdamped?

Unless it is a C.Bechstein or Bluthner, then unfortunately many of these instruments are of inferior quality or not serviceable and so have little to no value. In fact in many cases they will actually cost money to have them taken away and disposed of. The best thing would be to list on Gumtree, Facebook Marketplace, or ebay with a small price and condition that whoever buys it takes it away for you to avoid the costs.

Want to learn more about how pianos work? Explore our guide to wood types here, or discover the rich history of the piano here. Do you have an overstrung, underdamped piano that you’re interested in selling? Visit our sell my piano page here.

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