The result of the blind test is "a tone loved by people's ears." With consideration of acoustic psychology, a new speaker has been completed here.

The most significant feature of the Natural Sound Speaker is that it employs a new material called "special expanded polystyrene" for the diaphragm. While Yamaha based its research and experience on conventional practices in the audio industry, it developed the diaphragm's material with entirely new ideas without being bound by industry customs.

After conducting comparative experiments with various materials such as wood, paper, and metal, it was concluded that a high-quality special expanded polystyrene is ideal for the diaphragm. 

• This material is lightweight and durable, and it has rigidity when increasing the vibration area, even when compared to a paper cone. 
• It is not affected by humidity, and it has high durability and no aging over time. 
• It also allows for easy standardization of physical quality characteristics.

By adopting this special expanded polystyrene material from this new perspective, the Natural Sound Speaker was able to increase the vibration area to an ultra-large size. Therefore, it reproduces a rich and extended low-frequency sound. On the other hand, because the vibration width can be small, it has excellent linearity, and it can provide ample and generous playback sound without distortion at high input volume.
Additionally, due to its large, flat size, the reproduction sound becomes a "surface sound source," providing excellent sense of presence and sound expansion, making it an ideal specification for stereo playback.
Furthermore, the shape of the Natural Sound Speaker may seem strange compared to conventional speaker units, but it was not designed to be flashy. During the research and development stage, more than 200 different unit prototypes were produced, taking into consideration not only electrical and physical characteristics but also sound quality and tone. As a result of careful consideration, the current shape was determined, with all the subtle curves embodying the Natural Sound Speaker itself.

Inventing a Super Anisotropic High-Performance Magnet

Alongside the development of the speaker unit, research on the magnet, which can be considered the heart of the speaker, was also conducted. Yamaha's patented "Zone Melting method" produced a powerful magnet, the YM-5S, which is said to be the strongest magnet in the world. This development established the definitive foundation for Yamaha's speaker manufacturing process.

In order to further improve this speaker for Hi-Fi use, Yamaha introduced the world's first attempt at "acoustic psychology" and pushed research even further to create a speaker that doesn't simply produce sound, but rather allows the listener to experience music.

Yamaha's long experience in instrument making had taught them that audio equipment must not only improve the "electrical and physical characteristics such as frequency and distortion properties", but also consider other aspects. Based on ample data gathered from past experiences, and by using actual listening tests as the basic approach, they conducted comparative listening tests with people of all "classes" in various environments. From this, they derived the ideal sound quality for a speaker that enables one to listen to music.

Super large. An abstract single board. Made of a special synthetic material.

The reason for the unappealing design of this speaker is that the soundboard of an upright piano is not an exact rectangle, but rather a modified shape with the corners cut off to produce complex vibrations. The unique shape of the Natural Sound Speaker was born after more than 5,000 unit manufacturing and listening tests.

Why is the unit surrounded by cast metal?

The principle of a corn-type speaker is designed so that "vibration is infinite." Therefore, it is necessary to put it in a box and resonate it.

For a natural sound speaker, the repetition of vibration waves and their collisions become "complex vibrations," so the unit is surrounded by "very hard cast metal."

Therefore, even if the unit is not put in the cabinet in a "naked state" and sound is produced, there is no change in the effect of that sound.

The principle is the same as the soundboard of a grand piano. Theoretically, a large vibrating plate is good, but technically, the ability of the "magnet part responsible for the electrical part of the speaker" is an important factor, so the size of the unit is determined while taking that into account.

The difference between conventional corn-type units and natural sound speakers is that even with the same level of electrical input, the burden on vibration is significantly less for natural sound speakers, and if they receive the same level of vibration, the difference in output (size) of the sound becomes very large.

Therefore, the natural sound speaker unit does not have to endure unreasonable stress and its durability continues almost permanently.

In particular, in the case of corn-type units, if there is a hole in the unit, the sound becomes extremely poor. However, in the case of natural sound speakers, even if a "mouse gnaws a hole," there is no change in its characteristics.

Natural sound speakers are applying for over 30 patents worldwide, including magnets, frames, rims, the depressed part in the center of the unit, and shape.

Many of these features could be called patents without exaggeration. After its unveiling at the 1967 Audio Fair in New York, it has garnered attention from the audio industry and fans worldwide and has received a flood of inquiries from globally renowned audio makers.

We will answer various questions from audio enthusiasts.

Question 1: Why does the speaker have such a peculiar abstract shape?

• Answer: It is designed to emit sound through flexural motion, similar to the resonance board of a piano or violin. It is based on the principle of natural basic vibration, such as the movement of sound waves in a room, rather than artificial vibration. Furthermore, after studying acoustic psychology, only the advantages of flexural motion were extracted and reflected in the product.

Question 2: What are the advantages of enlarging the vibration plate?

• Answer: 1) The bass becomes richer and more powerful. 2) The sound is heard not only from the "axis direction" of the speaker, but from the "entire range." 3) Vibration is reduced and hiss is eliminated.

Question 3: What is the purpose of the rib-shaped wave pattern on the back of the speaker?

• Answer: The larger the speaker, the richer the bass reproduction, but at the same time, the higher frequencies become weaker. To overcome this problem, Yamaha attached "ribs" to the entire surface of the vibration plate to diffuse high frequencies. The design of the rib pattern is intended to further enhance important flexural motion.

Question 4: What role does the magnet play in sound reproduction?

• Answer: The magnet is the driving part of the speaker and the most important component. A powerful magnetic force greatly increases the sound output level. The Natural Sound Speaker uses a super-anisotropic magnet developed by Yamaha, which has significantly higher performance than other magnets. If another magnet were used in this speaker, the weight of the driving part would double.