Sound is said to be propagated as wave motion. This is only true in a large room with no obstruction. In reality, however, sound waves move in much more complicated way, colliding and jostling here and there, sometimes in a whirl. We audio engineers should try to visualize in our head how the sound waves are behaving, which cannot be explained by electrical theory. There seem to be still countless unknown factors challenging audio engineers. The more you think about audio, the deeper it appears to become.

Solemn Sound

Two hundred Zen monks begin prayer at five o'clock every morning at the Soji-ji, the head temple of Zen Buddhism. The monks sitting in the left and right files serenely recite sutra-chanting. What a solemn tone! This daily ritual invites people to the world of nirvana. What should I do if I am requested to express this solemnity with the sound reproduction equipment?

First off, I must think of how to collect the sound. According to the current recording method, a number of microphones would be placed in various locations like chessmen. But I am skeptical about this method, primarily because the more microphones are used, the more emphatically the original sound near the microphones is recorded, thus disturbing the sound wave harmony that most counts. Just imagine the noise emitted from a twin-engine plane. It may sound like "Brrr...", which is produced by subtle differences in frequency. Most musical instrumients or vocal congregations always produce "difference tone". It seems to me that this gentle trembling vibrates harmonics, further producing chords and as the result, a beautiful tone. If you want to produce a beautiful tone, you must first think of the mechanism in which it is produced.

Analog Sound Is Digital Sound

The analog disk does not always mean to have analog sound, nor the digital disk digital sound. To me the audio systems now available on market sound like digital even in their analog-processing stage. Each note sounds as sharp and acute as the square wave. It is Iike digital photo prints showing every detail of the object so clearty. Its first impression is superb and its resolution is of first rate, yet I wonder if this is the royal road to audio.

The kind of sound that I want to produce is such that its individual particles might have correlation. It is easy to produce so-caled "mellow" sound by choosing proper parts and circuits, but this "melow" property is tricky. It is a technique to gradate boundary lines. Vacuum tubes of 30 years ago happened to produce such a sound and this trend still continues. If any change ever occurred, it can be said that digital-like sound has been added. I cannot agree to this trend. I want to produce a sound in which its individual particles may radiate energy into the ambient space just like the sun and fuse into one. After all, I think I must go back to the stage of picking up sound. Sound of Electron

Have you ever seen the movements of electrons? The textbook says that the electrons move around the protons with a furious velocity. Sometimes I can vlsualize those movements very clearly. They are the behaviour of the thermoelectrons. The sound produced by the efficiency-oriented vacuum tubes is heavy whle the one by the vacuum tubes of simple structure is transparent. I imagine that this difference might lie in the relationship of the magnitude of the emission to the plate voltage. The thermoelectrons float around the heater or cathode like a sea of clouds. The bigger the emission, the more the thermoelectrons. Each thermoelectron must be separated from the clouds and be made to reach the plate. This process is related to the voltage applied to the plate.

Let's think of the structure of the pentode tube. Electrons overflow from the cathode, forming huge clouds. As the primary grid with a fine mesh controlling the electrons stands up nearby, the floating thermoelectrons are at a loss with the electron and grid, both negative. It seems to me that this state might have something to do with the "melow" sound produced by the pentode tube. Then, how can you reduce the floating electrons? In conclusion, there will be no alternative but to adopt a coarse mesh for the grid like VT-C and raise the plate voltage, using the directly heated triode. But now the heater becomes shaky, rattling the electrons, which is to affect the sound. How difficult audio is!