## 6 Results and Discussion
The simulated curves (Figure 7) also showed similar trends to those of measured curves, thus confirming and validating the ECM model. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Uper and Lower Boundary** & **10 Times** & **20 Times** & **30 Times** & **40 Times** & **50 Times** \\ Coefficient of variation & 5.05 \(\times\) 10\({}^{-9}\) & 1.87 \(\times\) 10\({}^{-11}\) & 1.36 \(\times\) 10\({}^{-10}\) & 2.37 \(\times\) 10\({}^{-9}\) & 0.285395 \\ \hline \end{tabular}
\end{table} 
Table 6: Optimization of acoustic resistance of ventilation cloths, upper and lower boundary tests (Remarks: 30 particles, 50 iterations). \begin{table}
\begin{tabular}{c c c c} \hline
**Ventilation Cloths** & \multicolumn{3}{c}{**Number of Iterations**} \\ \hline  & **50** & **100** & **150** & **200** \\ \hline
**Number of Particles** & \multicolumn{3}{c}{**Coefficient of Variation (Standard Deviation/Fit Value)**} \\ \hline
20 & 0.159409265 & 0.159409265 & 0.159409265 & 0.159409265 \\
30 & 5.05 \(\times\) 10\({}^{-9}\) & 4.71 \(\times\) 10\({}^{-9}\) & 4.71 \(\times\) 10\({}^{-9}\) & 4.71 \(\times\) 10\({}^{-9}\) \\
40 & 5.60 \(\times\) 10\({}^{-13}\) & 6.54 \(\times\) 10\({}^{-12}\) & 6.57 \(\times\) 10\({}^{-11}\) & 6.57 \(\times\) 10\({}^{-11}\) \\
50 & 5.87 \(\times\) 10\({}^{-12}\) & 2.63 \(\times\) 10\({}^{-13}\) & 3.40 \(\times\) 10\({}^{-15}\) & 6.41 \(\times\) 10\({}^{-15}\) \\ \hline \end{tabular}
\end{table} 
Table 5: Optimization of acoustic resistance of ventilation cloths, particle number, and coefficient of variation (Remarks: The upper and lower boundaries are in the range of 10 times the original parameter value (10–0.1)). \begin{table}
\begin{tabular}{c c c c} \hline
**Ventilation Cloths** & \multicolumn{3}{c}{**Initial Value “a” (N:s/m\({}^{5}\))**} & **Upper and Lower Boundary** \\ \hline \(R_{qp}\) & 2.0 \(\times\) 10\({}^{7}\) & (10 \(\times\) a)–(0.1 \(\times\) a) \\ \hline
**Ventilation Cloths** & **Best Value (N:s/m\({}^{5}\))** & **Variation (\%)** \\ \hline \(NW\)-1\(\_\)R\({}_{qp}\) & 4.22701 \(\times\) 10\({}^{6}\) & 78.8645 \\ \(NW\)-2\(\_\)R\({}_{qp}\) & 7.17173 \(\times\) 10\({}^{6}\) & 64.1413 \\ \(NW\)-3\(\_\)R\({}_{qp}\) & 1.04271 \(\times\) 10\({}^{7}\) & 47.8641 \\ \(NW\)-4\(\_\)R\({}_{qp}\) & 1.71071 \(\times\) 10\({}^{7}\) & 14.4643 \\ \(NW\)-5\(\_\)R\({}_{qp}\) & 1.93987 \(\times\) 10\({}^{7}\) & 3.0064 \\ \(M\)-250\(\_\)R\({}_{qp}\) & 3.54943 \(\times\) 10\({}^{6}\) & 82.2528 \\ \(M\)-300\(\_\)R\({}_{qp}\) & 4.27662 \(\times\) 10\({}^{6}\) & 78.6169 \\ \(M\)-350\(\_\)R\({}_{qp}\) & 5.94194 \(\times\) 10\({}^{6}\) & 70.2903 \\ \(M\)-400\(\_\)R\({}_{qp}\) & 1.20654 \(\times\) 10\({}^{7}\) & 39.6726 \\ \(M\)-450\(\_\)R\({}_{qp}\) & 5.25710 \(\times\) 10\({}^{6}\) & 73.7095 \\ \hline \end{tabular}
\end{table} 
Table 7: Optimized values of acoustic resistance of various ventilation cloths. Figures 8 and 9 show the measured and simulated results of the meshed ventilation cloths, respectively. The measured responses of microspeker with and without ventilation cloths show a definite effect. As aforementioned, the measured curves were influenced by the meshed ventilation cloths at mainly below 1 kHz. Moreover, as the number of meshes increased, the curves became lower and straighter below the fundamental resonances. The frequency range after 1 kHz was flat until the start of spurious resonance. Figure 6: Measured frequency responses of microspeker without and with non-woven ventilation cloths (NW-1 to NW-5). Figure 7: Simulated frequency responses of microspeker without and with non-woven ventilation cloths (NW-1 to NW-5). Figures 6 and 7 show the measured and simulated frequency responses of microspeeaker without and with non-woven ventilation cloths (NW-1 to NW-5). Additionally, Figure 10a,b illustrate the comparison of measured and simulated frequency responses of microspeeaker without and with non-woven ventilation cloths (NW-1 to NW-5). The measured and simulated responses show a good match, indicating that the ECM model can accurately predict the frequency response of microspeeakers.