Charbonneau G, Sudraud M
Bull Eur Physiopathol Respir. 1985 Jan-Feb;21(1):49-54.
We measured the frequency response of eight stethoscope membranes and of thirteen types of stethoscopes. Measurements were made in an anechoic chamber calculating the ratio between the intensity of a sinusoidal sound coming from a loud speaker and the intensity of the transmitted sound through the membrane of the stethoscope. Small membranes have a bandwidth (without attenuation or amplification) between 10 and 600 Hz while large membranes have a bandwidth twice the size (10-1200 Hz). This good result does not appear in the case of stethoscopes showing increasing attenuation versus frequency, with a mean value from -2.5 to -10.5 dB and variations of 10 dB in the range 50-1200 Hz which is the useful bandwidth for cardiac and pulmonary auscultation. By contrast, fidelity of the measured stethoscopes was good. Discussion of the results suggests modification of stethoscope design to eliminate faults of sound transmission and to elaborate a microphone sensor allowing an electric transmission.
我们测量了八个听诊器膜片以及十三种听诊器的频率响应。测量是在消声室中进行的，计算来自扬声器的正弦声音强度与通过听诊器膜片的传输声音强度之间的比率。小膜片的带宽（无衰减或放大）在10至600赫兹之间，而大膜片的带宽是其两倍（10 - 1200赫兹）。对于那些随频率衰减增加的听诊器，情况并非如此，其平均值在 - 2.5至 - 10.5分贝之间，在50 - 1200赫兹范围内变化10分贝，而该范围是心脏和肺部听诊的有用带宽。相比之下，所测听诊器的保真度良好。对结果的讨论表明，应改进听诊器设计以消除声音传输故障，并研发一种允许电传输的麦克风传感器。
