Spectral Response of Acoustic Guitars

Home , Acoustic guitar, Resonator guitar

University of Southern Maine USM Digital Commons

Thinking Matters Symposium 2020 Thinking Matters Symposium

May 8th, 12:00 AM

Carly Lavallee University of Southern Maine, [email protected]

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Lavallee, Carly, "Spectral Response of Acoustic Guitars" (2020). Thinking Matters Symposium. 10. https://digitalcommons.usm.maine.edu/thinking-matters-symposium/2020/poster-sessions/10

This Poster Session is brought to you for free and open access by the Student Scholarship at USM Digital Commons. It has been accepted for inclusion in Thinking Matters Symposium by an authorized administrator of USM Digital Commons. For more information, please contact [email protected]. Spectral Response of Acoustic Guitars Carley M. Lavallee University of Southern Maine Department of Mechanical Engineering

Abstract The resonator guitar is essentially an acoustic guitar. However, it is constructed in such a way that the sound is magnified. They were initially constructed to allow for the sound of the acoustic guitar to be amplified without additional equipment. Essentially, the sound resonates through built in metal cones which are located in the body of the guitar [1]. For this project the frequencies given off by the notes of the resonator guitar will be fed into a system, which will give the output frequency in a measurable form. Modal analysis locations will be identified and measured by both accelerometers and broadband microphones. This measuring system will be designed, created and tested to confirm its function. Spectral response of the resonator guitar will be compared to a standard acoustic guitar. Then a set of labs will be developed for use in future engineering classes such as vibrations and/or acoustics.

Objectives To compare the quality of the acoustic and resonator guitars to Sound Booth Setup see how they differ from one another.

Acoustic Time Fundamental 1st 2nd 3rd String Duration (s) Frequency (Hz) Harmonic Harmonic Harmonic E2 8.981 85 170 255 340 A2 19.833 111 222 333 444 Acoustic E2 (top) String FFT Resonator E2 (top) String FFT D3 6.428 148 296 444 592 G3 5.031 197 394 591 788 B3 12.805 242 484 726 968 E4 11.442 329 658 987 1316

Resonator Time Fundamental 1st 2nd 3rd String Duration (s) Frequency Harmonic Harmonic Harmonic E2 13.776 90 180 270 360 A2 6.416 111 222 333 444 D3 10.493 143 286 429 572 Acoustic E2 (top) String TFFT Resonator E2 (top) String FFT G3 11.876 197 394 591 788 B3 11.282 248 496 744 992 Results E4 4.685 329 658 987 1316 Guitar quality is generally measured but the length of time the sound of a note is sustained. The better the guitar the longer the sound produced lasts. Quality is also related to the resonances of the fundamental frequency. For the two guitars tested, it can be seen in Tables 1 and 2, the resonator guitar Acknowledgments string do not have equal quality in all strings as it should. The same appears to be true for the chosen Dr. James Masi for all his guidance and support. acoustic guitar. Also, the acoustic seems to be less high-pitched than the resonator, this can be seen by The UROP Fellowship for allowing me the comparing their TFFT’s in Figure 14. From this data collected it is hard to determine the quality of these opportunity to be a part of this project. two guitars. To get a more accurate result more testing will need to be performed.