A Mathematical Images Group Model to Estimate the Sound Level in a Close-Fitting Enclosure

<table>Plan view of the <svg height="7.9499998" id="M3" style="vertical-align:-0.11285pt" version="1.1" viewbox="0 0 9.625 7.9499998" width="9.625" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
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q0 16 13.5 31.5t28.5 15.5q12 0 17 -11q5 -10 25 -10q22 0 57.5 36t89.5 111l-40 108q-22 58 -36 58q-21 0 -67 -57l-19 20q81 107 125 107q17 0 30 -22t39 -88l22 -55q68 92 108.5 128.5t74.5 36.5q20 0 32.5 -14t12.5 -30z" id="x1D465"></path></g>
</svg>-<svg height="8.4250002" id="M4" style="vertical-align:-0.17555pt" version="1.1" viewbox="0 0 8.5874996 8.4250002" width="8.5874996" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,.062,8.013)"><path d="M475 445l-64 -69q-119 -128 -289 -280q27 6 81 -15q66 -26 102 -26q48 0 111 93l23 -19q-41 -84 -75.5 -116.5t-73.5 -32.5q-37 0 -147 53q-43 21 -63 7q-22 -15 -38 -41q-4 -7 -11 -7q-8 10 -8 26q0 38 47 83l292 273q-32 -5 -67 -1q-63 7 -105 7q-32 0 -53.5 -22
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</svg> plane showing the multiple machine radiating surface and front wall images of the infinitesimal point sources at the machine radiating surface. This is group number 1, the main reverberation. Since machine radiating surface is a baffled source, each image is a double spherical source. The overall effect can be viewed as a discrete line-type source.</table>

Advances in Acoustics and Vibration

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Figure 2

Figure 2: A Mathematical Images Group Model to Estimate the Sound Level in a Close-Fitting Enclosure 