Research and Development

A.R.E. Technology

A.R.E.処理を施した木材で作られたバイオリン

Acoustic Resonance Enhancement (A.R.E.) is a revolutionary wood reforming technology . Within a short period of time, new wood matured with this technology produces a tonal richness like that of well-used vintage instruments. A.R.E technology uses specialized equipment that precisely controls temperature, humidity, and atmospheric pressure to transform new wood to have the rich tone of instruments that have been played for many years. Furthermore, as no chemicals are used in the treatment process, A.R.E. technology has low environmental impact.

Beginnings of A.R.E Research Derived from Violin Development

The origins of A.R.E. technology date back to the late 1990s and arose from the research conducted by Yamaha Corporation to commence the manufacture of violins. Famous violins made 200 or 300 years ago are well known for the wonderful tones they produce. We researched why the wood in old violins makes such a sweet sound and, for part of the research into violin manufacture, made it our mission to look into materials that give a sweet sound and realize the same sound quality with reformed young wood. Wood undergoes substantial change as a result of heat and humidity. Young wood gives an edge and hardness to the sound, but, as the years pass by, it becomes more and more difficult for changes to occur and it produces a good deep, rounded sound. This “maturity” was thought of as one of the points to improving sound quality, and a variety of techniques, including chemical treatment and boiling, was examined to accelerate ageing in a short period of time. Of these numerous approaches, we came to the conclusion that the safest and most efficient technique for improving sound quality was by precisely controlling temperature, humidity, and atmospheric pressure.

Wood’s Special Characteristics Produce the “Sweet Sound”

Improving the quality of wood so that it would produce a “sweet sound” necessitated examining whether the sensuous “sweet sound” had some kind of physical properties. Many violinists have verbally assessed the “sweet sound” as “well settled,” “deep,” “matured,” “warm,” and as having “excellent resonance .” Translating these sensory evaluations into physical properties resulted in an understanding of the characteristics in acoustic terms, such as enhanced low-range sustain, improved levels of medium- to high-range attack, as well as short decay caused by a dissonant high-frequency component after the attack .

So what qualities does “matured wood” have that realizes this sweet sound?

Typically, wood is made up of fibrous cellulose and resinous lignin as well as a substance known as hemicellulose that binds these together. Old wood, in which the cellulose has crystallized, hardens in the direction of the grain. On the other hand, the amount of hemicellulose decreases, thus making it easier to remove across the grain. As it becomes harder in the direction of the grain, wood becomes softer across the grain. Materials that have properties that vary depending on direction are said to display anisotropy, which in the case of wood progressively improves sound as anisotropy increases. In other words, wood has strong characteristics, responding well when an instrument is played, extending the low range, and rapidly decaying the high range. Emphasizing the qualities displayed by matured wood resulted in the development of A.R.E.

The differences in sound between a standard wood panel and one that has undergone A.R.E. treatment can be heard on the video below.

(The difference can be heard more clearly with headphones.)

Difference in Sound with A.R.E.
* The difference in sound, for instance the extended low range, can be better heard when listening with headphones.
Panel Material after A.R.E. Treatment
Standard Panel Material
Panel Material after A.R.E. Treatment

The performance examples given in the video can be heard on the video here.

Overview of A.R.E. Treatment

For the A.R.E. treatment, wood is first placed in a cylindrical metal pressure vessel, the internal temperature and humidity of which is controlled as the treatment process is carried out; the pressure is changed in stages. This enables the treatment process to be undertaken in a surprisingly short time if compared with the time needed to age wood.

Of particular necessity during the treatment process is the precise control of temperature, humidity, and atmospheric pressure, as well as setting the optimal amount of treatment. The result of experience and expertise spanning many years, the optimal value settings combine the “sweet sound” of a musical instrument and durability, the wood being treated during a precisely controlled process.

So, what changes does the wood undergo?

The Structure of A.R.E.
Standard Panel Material
Cellulose
Hemicellulose
Lignin
Panel Material after A.R.E. Treatment
Cellulose → Increased Crystallization
Hemicellulose → Decomposition/Reduction

At first, there was the problem that new wood overplays high-order harmonics (harsh sounds at frequencies higher than 10 KHz). The hardening in the direction of the grain and softening across the grain of the wood achieved by the A.R.E. treatment improves the clearness of the sound, making it unmuffled, and produces excellent resonance by enhancing low range sustain and increasing the attack in the medium- to high-range frequency bands.

Enabling the suppression of harsh sounds, A.R.E. can also give rise to well-settled, pleasantly warm tones.

Thus, new wood is transformed into the components found in vintage wood.

A.R.E.’s Special Sound Characteristics
L Series
L A.R.E. Series
Increased Attack Levels in Medium/Broad Frequency Ranges
Greater Extension of Low-Frequency Band Sounds
Faster Decay of High-Frequency Range

Example Applications

Beginning with violins, A.R.E. technology has been applied to wooden instruments, such as acoustic guitars and electric basses. The technology was also used for the stage flooring at the Yamaha Ginza Hall in Tokyo. The hall flooring easily transmits the vibrations from musical instruments, so the materials used for the flooring contribute greatly to a venue’s acoustics.

A.R.E. technology places importance on trees, which are easy to process, more lightweight, and sustainable thanks to planned afforestation and forest management. Structurally, trees are highly anisotropic, which makes wood an ideal material for musical instruments. At a time when we are continuously replacing items that were once made of wood—such as those used for construction and sports purposes—with others made of new materials, this is why we are still making many musical instruments with wood.

An Artida YVN500S acoustic violin made with wood that has undergone A.R.E. treatment
An L Series (LL36ARE) acoustic guitar made with wood that has undergone A.R.E. treatment

(Left) An Artida YVN500S acoustic violin made with wood that has undergone A.R.E. treatment

(Center) An L Series (LL36ARE) acoustic guitar made with wood that has undergone A.R.E. treatment

(Right) A.R.E. technology was applied to the wood used for the stage flooring at Yamaha Ginza Hall

A.R.E. Treatment Technology Glossary

Cellulose
Cellulose is the name given to the main component of plant fiber. Cotton consists primarily of cellulose.

Lignin
An organic polymer found in the cell walls of plants that forms the chief constituent of wood

Hemicellulose
A hemicellulose is one of a group of carbohydrates that surround the cellulose fibers in plant cells.

High-Order Harmonics
When some musical instruments are played, they emit high-pitched “ringing” sounds at integer multiples of double, triple, or four times the fundamental frequency . These sounds are known as high-order harmonics.

(Sound) Attack
The period between a note being struck on a musical instrument and when the sound is first heard (or that phenomenon)

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