The Heart of the Piano: Essential to Tone and Volume Soundboard, Soundboard Ribs, Bridges
Bridges• Sound is the result of air molecules moving the inner ear. The vibrations of the strings must be accurately and efficiently transmitted to the soundboard by the bridges to produce this phenomenon.
• There is a long (tenor-treble) bridge and a short (bass) bridge, both attached to one side of the soundboard.
Soundboard• The string vibrations pass through the bridge to the soundboard which then resonates, increasing the volume and beauty of the sound to optimal levels.
• The soundboard is one of the most important factors in determining the overall beauty and dynamics of piano tone.
• The soundboard is constructed of many strips of carefully selected straight grain spruce wood, edge glue together to create the large area needed.
Soundboard Ribs• The soundboard ribs are attached to the rear of the soundboard at right angles to the grain of the wood. They serve to transmit string vibrations to every area of the soundboard.
• Combined with the bridges, they also serve to increase the strength of the entire soundboard assembly.
Soundboard + Soundboard Ribs + Bridges• The soundboard is not flat. Rather it's shape is part of a sphere with the center of the bridge side several millimeters higher than the perimeter.
• This curve shape is called the crown, and is essential to create a crisp and clear sound. The crown presses the bridges against the strings and thus insures sufficient contact to produce good tone.
Materials
• The soundboard uses spruce from Alaska and Romania. Spruce has many favorable characteristics: its light, flexible and elastic; it is strong, has straight grain and transmits vibrations quickly and very efficiently. Proved by piano builders for over 200 years, spruce is the wood best suited for producing find piano tone.
• By purchasing massive quantities of spruce in log form, Yamaha can select the best portions for soundboard construction.
• At Yamaha, the spruce lumber is slowly and naturally ages for a long period of time, then further cured by computer controlled kiln drying. The manner in which the wood is seasoned has a very large impact on the tone of the completed piano.
Design• To develop the best tone, proper design of the stringing scale (the placement, size, tension and length of the strings) along with the design and placement of the bridges is very important.
• Based upon many years of research, experimentation and constant improvement, Yamaha designs individual scales for each model, and this attention to detail has earned Yamaha the reputation of creating pianos possessing a well balanced, beautiful sound.
• High class models of upright pianos have many special engineering improvements in the area of scale design. As an example, to better accommodate both the need for longer strings and proper bridge contact with the soundboard, a long "overhanging" bridge was designed. With an innovative mounting system that increases flexibility at the base of the long bridge, the overhanging bridge creates a smoother transition of sound. In another case, by using a curved short bridge, rather than the less expensive to manufacture straight bridge, these models improve the gone quality in the lower register, and have a smoother transition of sound where the strings change from single string unisons to double string unisons.
Fabrication Technology• Yamaha has developed special techniques, machinery and separate facilities dedicated to producing the finest tone producing soundboard assemblies in the industry.
• But tone is not the only merit of Yamahas' soundboards. In addition, their strength and durability is unsurpassed. Even after years of use, the crown of the soundboard remains intact and will not sag or allow the bridges to lose proper contact with the strings.
