A study of mechanical pipe organ actions and how they influence musical performance

管风琴的动作是从手指移动的键到允许空气进入管道的阀门（托板）的链接。风琴师普遍认为，机械动作是可取的，因为从键到托板的直接链接允许演奏者对托板的运动进行一些控制，从而控制管道的开始和结束瞬变。这些瞬变现象（声音增强和减弱的方式）对于识别不同的声音至关重要。机械动作的特征之一是“拨弦”。这是克服托盘阀两端的压力差时对键运动的初始阻力。它被比喻为推动你的手指通过一层薄薄的冰。在拔出点之后立即控制指状件并因此控制托盘的运动是非常困难的。此外，有一些灵活性，即使是最刚性的行动，并有一些运动的关键之前，托盘打开。一旦托板开始打开，动作的其余部分的张力就会释放，导致托板弹开;这进一步降低了控制托板随后运动的可能性。到目前为止进行的实验表明，当演奏者认为他们正在改变键运动时，他们会做出节奏变化，以便做出表现性的变化。在弹拨点之前，钥匙的移动也有明显的变化，这取决于玩家认为他们正在移动钥匙。这种变化在托盘打开期间的关键拔出后运动中不明显。这个项目的主要目标之一是测试这一假设，即表达主要是通过微妙的控制音符间的时间，而不是通过修改的初始瞬态的注意。在演奏过程中，键的运动和器官动作的其他部分将被测量，以及声音输出的记录。一些专业选手将参与测试，测试将在各种器官上进行，包括一个专门建造的实验室仪器。在大型机械动作器官中，必须在重复率、键力和灵活性之间进行折衷，这通常会导致令人不舒服的沉重动作。最近的一些大型器官已经提供了替代的电作用，有证据表明，电作用几乎完全优先于机械作用。这种重复可能导致一种或两种行动中的不希望的妥协以及显著的额外成本。该项目的另一个目标是与斯图加特的同事合作，开发能够准确模拟器官机械动作特征的软件。其目的是为风琴制造商提供一种可靠的手段来预测计划的机械动作风琴的触摸特性。风琴风箱遵循相同的基本形式，他们已经有几个世纪，和托盘阀的设计缺乏科学基础。基于激光的技术将用于获得托盘阀周围气流的详细分析，以便更深入地了解托盘设计对机械动作器官的触觉和声音的影响。

The action of a pipe organ is the link from the key moved by the finger to the valves (pallets) that admit air to the pipes. There is a widespread belief among organists that mechanical actions are desirable because the direct link from key to pallet allows the player some control over the movement of the pallet, and thus over the starting and ending transients of the pipes. These transients (the way that the sound builds up and diminishes) are critical to the recognition of different sounds.One of the characteristics of mechanical actions is 'pluck'. This is an initial resistance to the movement of the key as the pressure difference across the pallet valve is overcome. It has been likened to pushing your finger though a thin layer of ice. It is very difficult to control the finger immediately after the pluck point, and thus to control the motion of the pallet. In addition, there is some flexibility in even the most rigid action, and there is some movement of the key before the pallet opens. As soon as the pallet does start opening, the tension in the rest of the action is released, causing the pallet to spring open; this further reduces the possibility of controlling the subsequent motion of the pallet.Experiments carried out so far show clear evidence that players make rhythmic variations in order to make expressive changes when they believe that they are varying the key movement. There are also clear variations in the key movement before the pluck point depending on how players think that they are moving the key. This variation is not evident in the critical post-pluck movement during which the pallet is opening. One of the main goals of this project is to test the hypothesis that expression is achieved primarily through subtle control of inter-note timing, rather than through modification of the initial transient of the note. The motion of keys and other parts of the organ action during playing will be measured, together with recordings of the sound output. A number of professional players will be involved in the tests, which will be carried out on a wide range of organs including a specially built laboratory instrument. In large mechanical action organs there has to be a compromise between repetition rate, key force and flexibility, often leading to an uncomfortably heavy action. Some recent large organs have been provided with alternative electric actions, and there is evidence that the electric action is almost exclusively used in preference to the mechanical action. This duplication can lead to undesirable compromises in either or both actions as well as significant additional cost. Another goal of this project is to develop software capable of accurate simulation of the characteristics of an organ mechanical action, in collaboration with colleagues in Stuttgart. The aim is to provide organ manufacturers with a reliable means of predicting the touch characteristics of a planned mechanical action organ. Organ windchests follow the same essential form that they have had for several centuries, and the design of pallet valves lacks a scientific foundation. Laser-based techniques will be used to obtain a detailed analysis of the airflow around the pallet valve, in order to obtain a deeper understanding of the effects of pallet design on the touch and sound of mechanical action organs.