著者
山本 晶万
出版者
一般社団法人 日本音響学会
雑誌
日本音響学会誌 (ISSN:03694232)
巻号頁・発行日
vol.44, no.8, pp.588-594, 1988
被引用文献数
2

ルーツブロワは容積型のロータリーブロワの一種で、最近では高性能自動車エンジンの過給機(スーパチャージャ)として使われ注目されている。構造が簡単で取り扱い気体に潤滑油が混入しない、回転数にほぼ比例した流量が得られる等の利点がある反面、大きな音を発生するのが欠点で、研究例が少なく発生機構の一部はまだよく分かってない。本研究では、問題になる吸気音をロータ回転角に同期させて、独自に考えたシステムによって3次元瞬間スペクトル解析を行ってその有効性を示すと共に、すでに行った研究で不明であったスペクトルの高域周波数で生ずるブロードピーク音は、ロータクリアランスの漏れ空気が圧力差の上昇によって、特定の回転角で増加してそれが音源になることを明らかにした。
著者
笹倉 豊喜
出版者
一般社団法人 日本音響学会
雑誌
日本音響学会誌 (ISSN:03694232)
巻号頁・発行日
vol.72, no.4, pp.207-212, 2016-04-01 (Released:2017-07-01)
参考文献数
8
著者
小林 哲則 関根 英敏
出版者
一般社団法人 日本音響学会
雑誌
日本音響学会誌 (ISSN:03694232)
巻号頁・発行日
vol.47, no.8, pp.539-544, 1991-08-01 (Released:2017-06-02)
被引用文献数
1

実音声における基本周期の揺らぎの統計的性質について調べると共に、規則合成のための揺らぎを考慮した基本周期生成モデルについて検討した。実音声の分析の結果、基本周期の揺らぎの系列相関は、35〜70次を周期とする減衰波状の概形を示すことが明らかになった。次にこの性質を考慮しながら種々の揺らぎを有する基本周期生成モデルを構成し、揺らぎの性質と合成音声の自然性との関係について検討した。聴取実験の結果、ARフィルタを用いて実音声における揺らぎの系列相関を合成音に与えるよう構成したモデルの性能が良いことが分かった。この揺らぎを有する基本周期生成モデルによる合成音声の自然性は実音声の揺らぎを用いた合成音声と同程度であることが示された。
著者
柴山 秀雄 福永 一保 城戸 健一
出版者
一般社団法人 日本音響学会
雑誌
日本音響学会誌 (ISSN:03694232)
巻号頁・発行日
vol.40, no.3, pp.152-160, 1984-03-01 (Released:2017-06-02)

This paper proposes a new pulse discharge sound source for acoustical measurements and discribes the construction and acoustical characteristics of the source. Existing pulse sound source generate sound sources generate sound pluse by a spark discharge using static energey in the charged condenser. The sound source proposed in this paper uses electromagnetic energy in a transformer. The current in the primaty turn of the transformer is cut off suddenly and a spark discharge is generated between the electrodes connected to the secondary turn. The timing of discharge is easily controlled by the electronic switch in the primarty turn. The duration of the sound pluse is very short and controllable and the power spectrum of the sound covers very wide frequencies. The extent of the nonlinearity is very small and the nondirectivity is realized. The reproducibility is good. The pluse discharge sound source proposed is useful for linear acoustical measurements
出版者
一般社団法人 日本音響学会
雑誌
日本音響学会誌 (ISSN:03694232)
巻号頁・発行日
vol.76, no.12, pp.734-735, 2020-12-01 (Released:2021-03-10)
著者
中林 克巳
出版者
一般社団法人 日本音響学会
雑誌
日本音響学会誌 (ISSN:03694232)
巻号頁・発行日
vol.30, no.3, pp.151-160, 1974-03-01 (Released:2017-06-02)
被引用文献数
3

This paper describes the sound localization on the horizontal plane. Fig. 1 shows the Loudspeaker arrangement for the experiments of directional hearing made. An observer sits on a chair with a headrest as shown in Fig. 2. The observer's head is slightly supported by the headrest. The observer gives the perceived direction of sound source presented. The results of the experiments of the directional hearing for these one-octave band noises can be divided into two groups (Fig. 3, 61%, and Fig. 4, 35%). The perceived direction of the observers of Fig. 3 is influenced by the signal frequency and the sound pressure level but that observers of Fig. 4 is not influenced by these factors. Table 1 shows the percentage of observers for each signal frequency and each judgement type. It is noteworthy that only the 8k - 16kHz one-octave band noise gives the correct judgement (74%). As for other four signals, the misjudgements are influenced by the signal frequency and the sound pressure level. As for the phantom sound source (see Fig. 7), the directional hearing for the one-octave band noise is shown in Fig. 8 and there occur many misjudgements. It is also noteworthy that the phantom sound source in the direction of 45゜ - 135゜ are not perceived in the direction of 45゜ - 135゜ but in the direction of 45゜ or 135゜ and that this phenomenon still occurs even if the band width of the signal becomes two octaves (Fig. 9). In order to find the factor which is effective for the correct judgement, three additional experiments are tried, the directional hearing of the real sound source, of two-octave band noise (Fig. 5), and of one-octave band noise with a certain amount of 8k - 16kHz one-octave band noise (Fig. 10), and the male voice cut off by a Low-Pass-Filter (Fig. 6). By these experiments, it may be said that the sufficient amount of the component of 8k - 16kHz, and widening of signal band are effective for the correct judgement and that the former is far more effective for the correct judgement and that the former is far more effective than the latter. Table 2 shows the percentage of observers of each one-octave band noise whose perceived direction is influenced by the sound pressure level. The ratio of observers whose perceived direction is influenced at least by two kinds of one-octave band noise is 53%. The relationship between the perceived direction and the sound pressure level is shown in Fig. 11 as a typical example. The perceived direction is determined independently of the loudspeaker direction. The last problem is the perceived direction of phantom sound source in the direction 45゜ - 135゜. This phenomenon can be explained by the calculation of ⊿P and ⊿ψ, where⊿P is the difference of the sound pressure level and ⊿ψ is the difference of the phase at the entrance of two external auditory canals (See Fig. 12 and Eq. 1 - Eq. 8). The results mentioned above are under the condition that the observers heard the signals in an echoless chamber with their head supported. Fig. 13 shows the relative frequencies of the directional hearing of 1/3-octave bands noise under the ordinary condition, without a headrest and in a laboratory room There still occur many misjudgements. These results and discussions can be applied to the recording technique of the 4-channel stereo.