Center for Computer Research in Music and Acoustics, Stanford University, 660 Lomita Drive, Stanford, California 94305, USA.
J Acoust Soc Am. 2012 Jan;131(1):963-73. doi: 10.1121/1.3651091.
Traditionally, the average professional musician has owned numerous acoustic musical instruments, many of them having distinctive acoustic qualities. However, a modern musician could prefer to have a single musical instrument whose acoustics are programmable by feedback control, where acoustic variables are estimated from sensor measurements in real time and then fed back in order to influence the controlled variables. In this paper, theory is presented that describes stable feedback control of an acoustic musical instrument. The presentation should be accessible to members of the musical acoustics community who may have limited or no experience with feedback control. First, the only control strategy guaranteed to be stable subject to any musical instrument mobility is described: the sensors and actuators must be collocated, and the controller must emulate a physical analog system. Next, the most fundamental feedback controllers and the corresponding physical analog systems are presented. The effects that these controllers have on acoustic musical instruments are described. Finally, practical design challenges are discussed. A proof explains why changing the resonance frequency of a musical resonance requires much more control power than changing the decay time of the resonance.
传统上，平均专业音乐家拥有众多的声学乐器，其中许多具有独特的声学品质。然而，现代音乐家可能更喜欢拥有一种声学可以通过反馈控制来编程的乐器，其中声学变量可以从实时传感器测量中估计出来，然后进行反馈，以影响被控变量。本文提出了一种描述声学乐器稳定反馈控制的理论。这一介绍应该能够让音乐声学界的成员理解，他们可能对反馈控制没有经验或经验有限。首先，描述了在任何乐器可移动性下保证稳定的唯一控制策略：传感器和执行器必须是共置的，并且控制器必须模拟物理模拟系统。其次，介绍了最基本的反馈控制器和相应的物理模拟系统。描述了这些控制器对声学乐器的影响。最后，讨论了实际设计挑战。一个证明解释了为什么改变音乐共鸣的共振频率需要比改变共鸣的衰减时间更多的控制功率。
