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Inverse Doppler Effects in Pipe Instruments
1Smart Materials Laboratory, Department of Applied Physics, Northwestern Polytechnical University, Xi'an, 710129, P. R. China.
Scientific Reports
|December 15, 2018
Summary
This study discovered inverse Doppler effects in recorders and clarinets, revealing these pipe instruments may be early acoustic metamaterials. This finding explains their historical popularity and aids future metamaterial design.
Area of Science:
- Acoustics
- Materials Science
- Musicology
Background:
- Pipe instruments like the recorder and clarinet have been historically significant in music.
- Acoustic metamaterials offer unique wave manipulation properties.
- Previous models explored acoustic metamaterials in flute-like instruments.
Purpose of the Study:
- To investigate the presence of inverse Doppler effects in common pipe instruments.
- To determine if these instruments exhibit characteristics of acoustic metamaterials.
- To provide a new perspective on the historical popularity of pipe instruments.
Main Methods:
- Experimental detection of inverse Doppler effects in recorders and clarinets.
- Measurement of effective refractive indices across musical pitches.
- Analysis of the instruments' properties in relation to broadband acoustic metamaterials.
Main Results:
- Inverse Doppler effects were detected across all seven pitches of an ascending musical scale for both instruments.
- The calculated effective refractive indices were negative and varied with pitch.
- These properties align with characteristics desired for broadband acoustic metamaterials.
Conclusions:
- Recorders and clarinets may represent the earliest known man-made acoustic metamaterials.
- The observed phenomenon offers a potential explanation for the widespread historical appeal of pipe instruments.
- This discovery could inform the design of next-generation broadband double-negative acoustic metamaterials.
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