In designing Stethocap™, one of our objectives was to insure that its use would not adversely affect the conduction of sound from the stethoscope diaphragm. Our design considerations included appropriate contour, fit, materials and appearance. The ultimate test was to determine if the use of the Stethocap™ would alter the audio frequency response of the stethoscope and impair or distort the conduction of sound of the stethoscope.
A high fidelity probe microphone was inserted into one of the earpieces of the stethoscope. A Tektronix T932 oscilloscope was used to measure the peak to peak audio response both with and without Stethocap™ in place. A high quality sine wave signal generator (DFG-600) was fed via an amplifier into high fidelity (Optimus) speaker. Response measurements were made from 50 to1000 Hz, the normal frequency band of interest for the stethoscope. ( A 1 D DB difference is considered the human threshold of ability to hear a difference in sound level.)
The test results demonstrated that Stethocap™ does not significantly alter the audio frequency response of the stethoscope. The variances found across audio frequency response levels were not significant and were at frequencies mostly below the human ability to detect a sound level difference. In fact, Stethocap™ enhanced the sound at 1,000 Hz.
DB Difference with StethocapTM on/off
Stethocap™ has been designed to precisely conform to the contour and surface area of the diaphragm to form a perfect fit with the surface of the diaphragm such that that there is no interference or static noises during auscultation.