日本音響学会誌
Online ISSN : 2432-2040
Print ISSN : 0369-4232
フルートの駆動条件と発生音圧レベルおよび基本周波数との関係 : フルートの実験的研究I
安藤 由典
著者情報
ジャーナル フリー

1970 年 26 巻 6 号 p. 253-260

詳細
抄録

A mechanical blowing apparatus was used in a simulation of flute playing for investigating acoustical properties of tones thus generated. Variations of sound pressure level and fundamental frequency with nine kinds of blowing conditions (Fig. 1, Tab. 1) (velocity, width and thickness of an air beam, sectional radius of lips etc. ), which are conceivable in actual flute playing, were measured on a head-joint made by Hermut Hammig attached to a middle- and foot-joint made by Muramatsu. The result is as follows. The sound pressure level (L, dB) is proportional to the velocity (u, m/sec. ) and width (w, mm) of an air beam. (Fig. 2) The other blowing conditions have no noticeable effects on L. ∂L/∂(20 log u)=∂L/∂(20 log w)=1 at the optimum value of u(=u_0) or w(7-10mm). (Fig. 3) With respect to u_0 and fundamental frequency (f, Hz), the following formula was found. log u_0=log 2. 4+1. 5 log(f/f_c^1)m/sec, where f_c^1 is the fundamental frequency of note c^1(=262 Hz). (Fig. 4) The lower soundable limit of u(U min) is usually about u_0/2, and the upper limit (U max) is about 2u_0. When the direction of an air beam is biassed inwards to the mouthhole properly (about 2mm) in the low register(c^1〜c^2) U max rises to about 4u_0, and high sound pressure level can be obtained. (Fig. 5) All the blowing conditions except the width of an air beam (w) have influence upon fundamental frequency f. But the conditions which have noteworthy influence are u and the length of an air beam (h, mm) (Fig. 6, 7). When u≧u_0, ∂f/∂(20 log u)=k. k×100=0. 23%, and the mean value of ∂f/∂h/f×100=0. 7[%/mm]. The level control in flute-playing was discussed on the basis of data obtained and actual observation of flute-playing (performed by P. Rampal, the author and others). The following conclusion has been reached. Permitting of no change in f, the probable dynamic range is about 16 dB [10 dB by width (w) control+6 dB by velocity (u) control] in flute-playing. In both controls (w and u), f is kept constant by adjusting the length of an air beam (h).

著者関連情報
© 1970 一般社団法人 日本音響学会
前の記事 次の記事
feedback
Top