The concept of 塩 e ac も ive sound cancellation contrQl of the railway wheel ！ rail noises by the On −vehicle − type devices is presented ． And the apparatus of ra 皿 do皿 ly excit 三 ng 60kg rail by the e 至 ectromagnetic shaker whidl js e ロ closed with the panel system si皿 ulating the fioor ／ side wall of も he railway car was constructed ， Fuエther ， Que unit of the devices which rea ユ izes in I 〕rinciple the sound cancellation coutrel of the seeth エ ough space was 皿 anufactu τed a 皿 d the parabola − mic エQpholle and aK； tuating speaker was instaユ 三 ed on it三 n addition to the controller consisting of the ana 三 〇 g electrical band − pass filter circuit group ． And it was verified that the sou 皿 d ca 皿 cellat 量 on con も rol effects are observed actually foT the both cases of a speaker and the randomly excited rail system which were Iegarded aS the primary seund sou エces ．

No abstract

Sound field reproduction is a promising technology for reproducing a desired sound field over a specific area. However, several practical challenges exist, such as the requirement for a large number of loudspeakers and the degradation of spatial reproduction accuracy due to room reflections. This work proposes a sound field reproduction method based on a cylindrical loudspeaker array that is used to both radiate sound directly towards the listener and take advantage of controlled first-order reflections from the room's walls. The sound field corresponding to one or more virtual sound sources is created by the combination of the direct and reflected sound at the listener position. As long as the lateral walls generate welldefined specular reflections, the simple model of the reverberant field with the proposed formulation enables this method to work without elaborate acoustical measurements. Two approaches with different concepts of controlling the array are compared and their mathematical equivalence is shown. To evaluate the performance, both simulations and experiments were conducted, showing a good agreement with theory.