PIANO CONSTRUCTION
What you should know about piano construction and terms
1. Aliquots — This is a system of stringing in which over half of the compass, an extra, unstruck string is added to each note. The Mason and Hamlin piano scale design, for example, features separate aliquots which are individually tunable to the speaking length of the treble string. Tunable aliquots are an original Mason and Hamlin design that yield a piano that is more harmonically accurate than those that have standard duplex scaled designs. That is one of the reasons why a Mason and Hamlin piano sounds more pleasing to the ear.
2. Agraffes — These are small brass fittings, with holes through which the strings pass, screwed into the plate of the pianos to keep the strings perfectly positioned and spaced. Installing Agraffes is a very expensive and tedious process, therefore is found usually in grand pianos only or more expensive European verticals.
3. Duplex Scaling — This is a system of stringing in grand pianos that was originally developed by Steinway in which the part of the string between the bridge and the hitch pin, where the string is anchored to the iron frame, passes over an “additional bridge” just in front of the hitch pin. This part of the string’s length is allowed to vibrate, thus altering the response of the long bridge to vibrations from the main speaking length. The extra vibrating section has a length which is in harmonic proportion (a whole number fraction) of the main speaking length. This improves the sound and sustaining qualities of the piano. Manufacturers such as Mason and Hamlin and Steigerman (Premium) employ the use of duplex scaling in their design.
4. Frame (or plate) — The frame, also referred to as the harp of the piano is made of cast iron. This is what makes a piano so heavy, regardless of the age. Cast iron is necessary because of the combined tension of the strings (20 tons or more) The tension must be supported by the back frame construction (a combination of the iron plate and back posts).
5. Bridges — The bridges are termination points on the speaking lengths of the strings. There is a bridge at each end of the speaking length of the strings-one on the iron frame, and one on the soundboard. There are generally three or four bridges altogether, the bass and treble bridge on the soundboard, and one or two on the iron frame. In some cases the iron frame will have Agraffes instead, which as mentioned above, are individual units, one per note, with holes through which the strings pass. Agraffes on upright pianos each have an individual bridge as part of the construction. The bridges on the iron frame, or Agraffes, provide a rigid boundary to one end of the string’s speaking length. On a grand piano the ridged bridge provided by the iron frame may be in the form of a capo, which bridges on top of the strings.
The soundboard bridges (bass and treble), transmit the vibrating string’s energy to the soundboard. Steel bridge pins are driven into the wooden bass and treble bridges to keep the strings in place, to assist in sound transmission and to terminate the vibrating portion of the string. The other end of the string terminates at the frame near the tuning pins. Wooden bridges are mostly made of maple or beech and can be either solid or laminated, and must be of sturdy construction to withstand over 600 lb. of downbearing pressure from the combined force exerted by the strings. Bridges should also be notched for each note, right along both sides so that each string has a more precise termination point.
6. Ribs — These are strips of wood glued to the back of the soundboard, perpendicular to the grain of the wood. They assist in transmitting the vibrations across the soundboard faster as well as maintaining the “crown” of the soundboard. The soundboard is under pressure from the downbearing of the strings but at the same time needs to be free to vibrate and allow the sound waves to travel through the wood for amplification. For this reason the soundboard is actually crowned in the middle and kept under tension by the assistance of ribs which can be seen at the back of any vertical piano, or underneath a grand piano. The ribs should be tapered at both edges to match the shape of the soundboard, thus providing greater support in the centre (the crown) where the soundboard is under greater curvature and pressure.
7. Soundboard — The soundboard is a giant wooden loudspeaker that vibrates in sympathy with the strings. Spruce (either solid or laminated) is usually used for this component because of its ability to transmit sound quickly. The best spruce for soundboard construction is grown in cold climates and produces tight, straight grains. Soundboards are never flat but rather need to be crowned or concave in order to have any power of transmission.
Violins and acoustic guitars also utilize spruce soundboards because of its sound transmitting properties. Some piano manufacturers use “solid spruce soundboards” while others use “laminated spruce soundboards”. Some of the so called laminated boards are not really laminated but rather solid boards sandwiched between two thin veneers of spruce for added strength and durability allowing the soundboard the ability to retain all of the sound projecting qualities of the “traditional” solid soundboard. Klaus Fenner, of Germany, one of the world’s leading scale designers told me that the most important aspect of soundboard construction is “what you do with the wood” rather than whether it’s solid or laminated. A solid spruce board that has lost its crown will sound weak and powerless whereas a laminated board which is properly constructed and crowned will sound clear and powerfull.
8. Voicing — This refers to the treatment that is given to hammers in order to either reduce the tension in the hammer felt or to harden the hammerfelt, thus affecting changes to the tone of the piano.
9. Regulation — Refers to the adjustments and setting of movements, distances, alignments and tensions of the various parts of the action. There are many thousands of action parts in a piano. These parts consist of wood, felt, metal, paper, leather, brass, steel and plastic that must work in relationship with one another with precision and accuracy. In order that a pianist has the level of control and power he desires, it is vital that the action be properly regulated.
10. Pinblock — The pinblock is a plank made of laminated layers of hard wood (usually beech or maple) attached to the cast iron plate and inner rim. The tuning pins are screwed into the pinblock through holes in the plate and have the individual piano strings wound around them. The purpose of the pinblock is to hold the pins firmly in place in order to ensure good tuning stability. For added strength and a stronger grip, the alternate laminations run at ninety degrees to one another.
11. Action — The action has often been referred to as the “heart” of the piano. As we have already mentioned in a previous section, there are basically two kinds of actions. For most vertical pianos a direct blow action is the best. The grand action operates more with the assistance of gravity as opposed to the springs and levers of a vertical action and is quicker and more responsive. The action is so critical because it is a sensitive mechanism which translates all the nuances which the pianist wishes to play directly to the hammers that in turn strike the strings. The action is one of the most subjective areas when selecting a piano. Some players prefer a lighter action while others prefer a heavier action. An action which is too light will not give the player enough resistance.
12. Pedals and Trapwork — Most pianos these days have three pedals. The trapwork refers to the entire pedal assembly with all its brackets and levers, rods as well as the pedals.
13. Sustain pedal — This is the right pedal and the one that is most commonly used. It lifts all the dampers, causing the notes to sustain and resonate.
14. Soft pedal — The left pedal on most modern vertical or upright pianos. It moves the hammer rest rail forward towards the strings so that the blow distance (distance between the hammers and the strings) is reduced thereby reducing the power of the action by introducing lost motion, or reducing the depth of touch (how far the keys can be pressed down at the front).
15. Practice pedal — Also referred to as a muffler pedal and found only on vertical models (middle pedal). Here a strip of felt drops between the hammers and the strings, to muffle the sound.
16. Sostonuto pedal — This refers to the middle pedal on most grands. When depressed it raises the dampers of notes whose keys are already depressed, leaving the other dampers unaffected. Sometimes a middle pedal on small grands will be referred to as the “sostenuto” pedal, when in fact it is really a “bass sustain” pedal and lifts all the bass dampers simultaneously. Some vertical pianos also employ the use of a genuine sostenuto pedal.
17. Hammers — These are the felt covered “hammers” that strike the strings when a key is depressed, producing the sound. Hammers come in different sizes, weights, types of wood and quality levels. The type of felt that covers the hammers also can vary considerably.
18. Dampers — These are soft, felt covered, wooden action components that are at rest in contact with the strings, preventing them from sounding. When a key is depressed, the damper of the affected note is lifted off the string, allowing it to sound.
19. Escapement — A mechanism by which the hammer is set free from the rest of the action pushing it towards the string, just before it strikes the string. This enables the hammer to bounce naturally off the string rather than blocking against it.
