# An Efficient Multistage Approach for Blind Source Separation of Noisy Convolutive Speech Mixture
## 4 Results and Discussion
### Subjective Evaluation
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Multivariate**} & \multicolumn{2}{c}{**Student’s T**} & \multicolumn{2}{c}{**Generalized**} & \multicolumn{2}{c}{**Proposed Model**} \\  & \multicolumn{2}{c}{**Gaussian**} & \multicolumn{2}{c}{**Distribution**} & \multicolumn{2}{c}{**Gaussian**} & \\ RT & \multicolumn{2}{c}{**Source Prior [31]**} & \multicolumn{2}{c}{**Source Prior [42]**} & \multicolumn{2}{c}{**Source Prior [32]**} & \\
**(ms)** & **MOS for \(\boldsymbol{S_{1}}\)** & **MOS for \(\boldsymbol{S_{2}}\)** & **MOS for \(\boldsymbol{S_{1}}\)** & **MOS for \(\boldsymbol{S_{2}}\)** & **MOS for \(\boldsymbol{S_{1}}\)** & **MOS for \(\boldsymbol{S_{2}}\)** & **MOS for \(\boldsymbol{S_{1}}\)** & **MOS for \(\boldsymbol{S_{2}}\)** \\ \hline
40 & 3.94 & 4.01 & 3.86 & 3.70 & 4.10 & 4.23 & 4.34 & 4.67 \\
80 & 3.72 & 3.79 & 3.52 & 3.39 & 3.94 & 3.86 & 4.21 & 4.18 \\
120 & 3.18 & 2.75 & 2.63 & 2.57 & 3.49 & 3.18 & 3.68 & 3.44 \\
160 & 2.81 & 2.58 & 2.46 & 2.43 & 2.95 & 2.87 & 3.03 & 2.96 \\
200 & 2.34 & 2.25 & 2.17 & 2.08 & 2.46 & 2.37 & 2.58 & 2.47 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Average MOS results of the subjective evaluation for the first model shown in Figure 1 with variable RT for multistage BSS models having different source priors. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Multivariate**} & \multicolumn{2}{c}{**Student’s T**} & \multicolumn{2}{c}{**Generalized**} & \multicolumn{2}{c}{**Proposed Model**} \\  & \multicolumn{2}{c}{**Gaussian**} & \multicolumn{2}{c}{**Distribution**} & \multicolumn{2}{c}{**Gaussian**} & \\
**SNR** & \multicolumn{2}{c}{**Source Prior [31]**} & \multicolumn{2}{c}{**Source Prior [42]**} & \multicolumn{2}{c}{**Source Prior [32]**} & \\
**(dB)** & **MOS for \(\boldsymbol{S_{1}}\)** & **MOS for \(\boldsymbol{S_{2}}\)** & **MOS for \(\boldsymbol{S_{1}}\)** & **MOS for \(\boldsymbol{S_{2}}\)** & **MOS for \(\boldsymbol{S_{1}}\)** & **MOS for \(\boldsymbol{S_{2}}\)** & **MOS for \(\boldsymbol{S_{1}}\)** & **MOS for \(\boldsymbol{S_{2}}\)** \\ \hline
0 & 1.91 & 2.08 & 1.74 & 1.63 & 2.21 & 2.26 & 2.43 & 2.39 \\
0 & 2.24 & 2.31 & 1.98 & 1.78 & 2.53 & 2.49 & 2.72 & 2.58 \\
0 & 2.81 & 2.67 & 2.46 & 2.27 & 2.98 & 2.81 & 3.15 & 3.04 \\
6 & 3.22 & 2.91 & 2.83 & 2.71 & 3.45 & 3.22 & 3.59 & 3.45 \\
8 & 3.39 & 3.21 & 2.96 & 2.88 & 3.62 & 3.47 & 3.82 & 3.51 \\
10 & 3.54 & 3.45 & 3.20 & 3.13 & 3.79 & 3.55 & 3.92 & 3.68 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Average MOS results of the subjective evaluation for the second model shown in Figure 2 with variable SNR for multistage BSS models having different source priors. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Multivariate**} & \multicolumn{2}{c}{**Student’s T**} & \multicolumn{2}{c}{**Generalized**} & \multicolumn{2}{c}{**Proposed Model**} \\  & \multicolumn{2}{c}{**Gaussian**} & \multicolumn{2}{c}{**Distribution**} & \multicolumn{2}{c}{**Gaussian**} & \\
**SNR** & \multicolumn{2}{c}{**Source Prior [31]**} & \multicolumn{2}{c}{**Source Prior [42]**} & \multicolumn{2}{c}{**Source Prior [32]**} & \\
**(dB)** & **MOS for \(\boldsymbol{S_{1}}\)** & **MOS for \(\boldsymbol{S_{2}}\)** & **MOS for \(\boldsymbol{S_{1}}\)** & **MOS for \(\boldsymbol{S_{2}}\)** & **MOS for \(\boldsymbol{S_{1}}\)** & **MOS for \(\boldsymbol{S_{2}}\)** & **MOS for \(\boldsymbol{S_{1}}\)** & **MOS for \(\boldsymbol{S_{2}}\)** \\ \hline
0 & 2.1  
white Gaussian noise. The clean estimated speech signals are marked with a higher mean opinion score (MOS) and vice versa. The results obtained from the listening participants for each extracted signal are averaged and presented in Table 5. In Table 5, the proposed model shows improvement in its MOS in comparison with the multistage BSS having source priors [31; 32; 42]. Next, the parameter RT was varied from 40 to 200 msec with a fixed window length = 512, NFFT = 1024, and SNR = 4 dB.