@@高橋敏幸-k8l さん 貴重な意見ありがとうございます。日本語が下手なので英語で書きます。The pipe organ is an example, but I think that the pipe organ is a comprehensive instrument in the building, hall, and interior. I worked for Philips, a company headquartered in the Netherlands, from the age of 16 to 52. At first, as a performance and recording engineer, I became a full-time employee after taking the university examination, and since the age of 30, I have hardly been in Japan, and I have been seconded to audio manufacturers and automobile manufacturers in various countries to develop various devices. Of course, I've also designed an equalizer. Equalizers and electronic echo circuits are a cut-and-try world where the constant number is determined until the very edge of sound discomfort. Nowadays, many people mistakenly think that software does everything, but the sound signal is separated for each band of music, and delay processing and gain processing are performed for each band, creating an equalizer and reverberation circuit. It's soft to tweak it. The starting point of the sound engineers I was taught was to provide sound sources with low distortion and noise, and to let each manufacturer decide how to season the sound. If that is not enough, I think it is good because it can be devised by individuals. Sound is people's preference. As a side note, I used to live in Philadelphia, USA, and now I am back in Japan and training young Confucian engineers at each manufacturerAnalog circuits, digital circuits, programs, many young people today are relatively more serious than in the past, and I am looking forward to 3~5 years from now. Look forward to the new equipment, the computer installed in the car is inexpensive and seems to have evolved considerably, and it seems that the parameters of the sound adjustment range can be increased.