You might have heard the term scale design used before and wondered exactly what it is. Well, the answer has a number of parts and can actually become fairly complex. I’ll do my best to explain exactly what it means and how you can spot the differences on your piano and others.
Scale design is something that is unique to each piano. It involves not only one aspect but the entire design of a piano in regards to how it produces tone. If you look inside a piano, you will notice that there are varying lengths of strings; the treble strings are shortest and then gradually get longer as you progress down to the bass strings.
Each piano actually has a slightly different geometry in how these strings get longer. Also, the strings have different diameters – the strings at the treble register are the thinnest and the strings along the bass register are the thickest. Some pianos will actually use what is called a high tension scale – which means that the strings are thicker but will have to be pulled with more tension in order to create the same pitch. Other pianos will have a low tension scale which is basically the opposite of high tension – the strings are thinner and require less tension. Is one better than the other? Not necessarily – these are just two different methods of achieving the desired tone.
This is not all when it comes to scale design; this is just the beginning!
Once you progress to the lower register of the piano you have copper wound strings. Where the copper wound strings begin is again part of the scale design of a piano. Believe it or not, the difference in where these copper strings start is different not only with different brands of pianos but in the different models of one manufacturer. For example, on the Steinway M I am using in this video, the copper strings start slightly before the register break.
What is a register break? This brings us to another important aspect of scale design. You probably notice that on your piano there is a section in which cross stringing occurs – where strings are crossed over one another; this happens in the lower register. The point at which the strings begin to cross over is called the register break.
Believe it or not, even the winding of the strings has something to do with scale design. Sometimes the copper wound strings start with the double strings and in the lower register become single wound. Other times there are even triple wound strings in the upper bass area as in my Baldwin SD-10 Concert Grand.
Another aspect of scaling is where the string is actually hit by the hammer. If you look at the action of your piano you will notice that the hammers strike the strings at specific points. This is done very deliberately to produce a certain tone. The exact point at which the strings are hit has a dramatic effect upon piano tone. If you have ever played guitar, you notice the different tones you get when plucking strings at different points from the bridge. It is the same with pianos.
There are other technologies when it comes to scale design as well. The non-speaking part of the string – the part beyond where the hammer strikes – can also have something to do with scale design. Some pianos have what is called duplex scaling. This allows the strings to resonate freely without muting them at these points – producing musically useful overtones. Other pianos have felt that will dampen the sound at these points because they are not designed to have them produce an additional tone. Is one better than the other? Again, not necessarily; while duplex scaling can enhance tone, it is not the only way that piano designers can achieve great results.
Another aspect of scale design is where the bridges are placed along the soundboard. This is again something that is very important in producing a certain tone in a piano. In fact, in the earlier pianos before cross stringing emerged, the bridges were placed along the edge of the soundboard. Modern pianos with cross stringing achieve better tone by having the bridges more centrally located on the soundboard.
The bottom line when it comes to scale design is what it sounds like. Sometimes pianos designed by computers are “perfect” in the mathematical sense but don’t necessarily offer beauty or warmth of tone that the slight imperfections may provide. This is truly part science and part art, but what’s most important is how the piano sounds and feels to you.
Another important factor is the environment the piano has been subjected to. An extremely dry or humid environment can damage a piano. Definitely look on the back of the piano at the soundboard for detached ribs, warping, or open cracks. (Tight, hairline cracks are not a concern.) Look for rust or corrosion on the strings. Yellowing of felt parts (hammers and dampers) also indicates parts that are more weather-worn.