Braasch Jonas
School of Architecture, Rensselaer Polytechnic Institute, Troy, New York, USA.
J Acoust Soc Am. 2008 Mar;123(3):1683-93. doi: 10.1121/1.2828062.
In this investigation, three different swell systems known in pipe organs, the swell box, the crescendo wheel, and the historic wind swell were measured and compared to each other. The dynamic range of the crescendo wheel was found to be most effective, and for frequencies near 2 kHz the increase in sound pressure level could be up to 50 dB between the softest and the loudest adjustment. The maximum dynamic range for the wind swell and the swell box were found to be 10-20 dB in the same frequency range. With its step-wise crescendo procedure, the crescendo wheel simulates the type of orchestra crescendo which is reached by successively adding further musical instruments. In contrast, the swell box and the wind swell produce a crescendo effect similar to the crescendo in which individual musical instruments perform a dynamic movement. This type of crescendo requires a continuous level increase but allows a smaller dynamic range. The disappearance of the wind swell is not surprising because it offers no advantage over the swell box, while being restricted to stops with free reeds.
在本研究中，对管风琴中已知的三种不同的渐强系统——音箱、渐强轮和传统风箱渐强装置进行了测量并相互比较。结果发现，渐强轮的动态范围最为有效，对于接近2kHz的频率，在最柔和与最响亮的调节之间，声压级的增加可达50dB。在相同频率范围内，风箱渐强装置和音箱的最大动态范围为10 - 20dB。渐强轮通过逐步渐强的过程，模拟了管弦乐队渐强的类型，即通过陆续添加更多乐器来实现。相比之下，音箱和风箱渐强装置产生的渐强效果类似于单个乐器进行动态变化时的渐强。这种渐强类型需要持续的电平增加，但动态范围较小。风箱渐强装置的消失并不奇怪，因为它相对于音箱没有优势，而且仅限于使用自由簧片的音栓。
