Al Tobias (wat4y) - Office: Rm. 201, (434) 924-0538 - Lab: Rm. 202, (434) 924-6800
Demonstrations are cataloged according to PIRA Bibliography
PLEASE REQUEST DEMOS WELL IN ADVANCE
Due to Physics Building renovations, the lead time to set up demo requests has increased due to the need to transport equipment across campus. Please be kind and let me know well ahead of time what you need.
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Equal Loudness Fletcher Munson Experiment
Purpose:To demonstrate that the sensitivity of human ear is frequency dependent.
Procedure:The demonstration uses the Fletcher-Munson box, two PASCO oscillators, a good fidelity PASCO speaker and an oscilloscope.
Connect two oscillators to the Fletcher-Munson box input. One oscillator is a reference signal and another is an adjustable signal. Connect one output of the box to a speaker and another to the oscilloscope. Set the same frequency of 1000Hz on both oscillators and adjust the level of the adjustable signal so it sounds as loud as the reference signal. Check on the scope for precise adjustment. Then change the adjustable frequency to 100Hz or 10,000Hz and compare the loudness wrt the reference signal again. Notice noticeable change in the loudness perception while the amplitude of all the signals on the scope remains unchanged.