A bamboo flute sounds sonorously, and a Japanese hand drum sounds tumtum


< Instruments which make impulsive sounds, such as a Samisen, a  Japanese hand drum, a Japanese drum and 

wooden clappers should create distinct soundswhile a bamboo- flute and spoken lines by a player should be  rich and mellow.>

- This is one of the requests from a player who performed in Japanese classical plays when I accepted, in 1965, to design the acoustics for National Theatre of Japan located in Miyakezaka. 

The request included conflict that the sounds of stringed instruments should rise clearly but the sounds of wind instruments and human voices should be vibrant. So, the request was a very hard one to satisfy, with the conflicting requirements for a theater or a hall where sounds of various instruments and human voices are mixed.

By the knowledge of those days, there was no other way but to design acoustics of a theater or a hall supposing locations of instruments and human voices in each program, considering a relationship between each time frame and sound quality being characterized as a direct sound, a diffused sound or a reflected sound in an echo time pattern of the room.

For the hanamichi where only lines are mainly delivered by a player, what kind of shape and material for its nearby wall and ceiling should be chosen? On the stage, the acoustics should be rather dead mainly for the strings. Angles of the reflectors and the wall should be carefully controlled to avoid the sounds  overlapping. Although I did my best to design these basic parameters, I still wonder how much I could respond to these requests in my acoustic design.

Now I consider whether I can incorporate some excellent technologies better than those of fifty years ago. I can divide the direct -sound part in the echo time pattern more precisely applying much advanced measuring methods. First I try to divide it into two periods. The direct sound I is the period when instruments and human voices arrive first. The direct sound II is the period during which the direct sound is enhanced. When I reconsider the rising of sound paying attention to the direct sound I, and the richness of sound to the direct-sound II, I could take part in solving the conflict I faced fifty years ago.

I had the above thought through my real experience of using our TGA loudspeaker basically designed making much account of sound-field reproduction. I realized then that the period of time with respect to the  direct sound I was very important at a listening point or a microphone‘s sound collection point.  Instruments and human voices are sound sources same as loudspeakers. 

Why don’t you consider this issue together?