Sound intensity and reflection coefficient measurements in the ear canal

Comparison between intensity and pressure as measures of sound level in the ear canal.

In-the-ear calibration of sound pressure level may be problematic at frequencies above 2 kHz, because the pressure can vary significantly along the length of the ear canal, due to reflection of sound waves at the eardrum. This issue has been investigated by measuring behavioral thresholds to tones in a group of human subjects (N = 61) for two different insertion depths of an insert earphone. Th...

Mass in the ear canal.

Estimation of Stapedius-Muscle Activation using Ear Canal Absorbance Measurements

The stapedius muscle, which is located in the middle ear, goes into contraction when the ear is exposed to high sound intensities. This muscle activation is called 'the acoustic reflex'. Measurement of the acoustic reflex is clinically of importance since it can reveal diagnostic information about the middle ear's pathologies. Moreover, this muscle-activation alters the acoustic characteristics...

Simulation of Microstrip Reflectometer System for Complex Reflection Coefficient Measurements

This technical paper presents a simulation of three probes reflectometer system for complex reflection coefficient measurement. This involves designing a circuit of Reflectometer using Genesys software. The simulation results and data from published Three-Probe Reflectometer measurement system is being compared to show the accuracy of the simulation results. Using the design circuit, a microstr...

On the subtraction method for in-situ reflection and diffusion coefficient measurements.

The subtraction method is a technique critical to several important acoustic measurements. It involves subtracting a reference measurement including only direct sound from one with direct sound and a reflection, to isolate the reflection. The process is very sensitive to environmental conditions, such as changes in temperature, air movement, and microphone positioning. These variations cause sm...