## 3 Results
### Cluster Analysis
#### 3.2.1 In-Situ Experiment Results  
Five clusters were found at an inter-construct distance of 40 and 10 clusters at a distance of 20. An overview of the clusters resulted from the analysis revealed a number of similar interactions between constructs across different clusters. Table 2 presents the main categories extracted from the cluster analysis. Whilst the observed clusters do not show a definite delimitation between the different attribute categories, certain aspects of spatial impression can be extracted from each cluster showing a possible perceptual or physical property. Different verbalisations possibly suggesting similar effects to ASW and LEV were observed. For instance, constructs such as \"source size\" (No. 5 in Figure A1) and \"horizontal spread\" (No. 1 in Figure A1) might indicate a perceived attribute similar to \"source width\" (No. 3 and 4 in Figure A1). As such, it is believed that even without a definitive attribute name, the perceptual effect can be linked to the more classical ASW. Attributes such as \"reverb width\" (No. 26) and \"environmental width\" (No. 23 and 25) might be associated with \"envelopment\" (No. 24), based on [10]. Again, multiple verbalisations could convey the same perceived spatial attribute of being \"surrounded by reverb\" (No. 28), which is in line with the classical LEV perceptual definition. The advantage of using RGT and cluster analysis can be well observed in cluster 3.3 (Figure A1). A small cluster formed by no. 29, 30 and 31 refer to physical properties of the reverberation (time, loudness, D/R \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{6}{c}{(a) **In-Situ Experiment**} \\ \hline
**Feature** & **Number** & **\%** & **dfe/afe** & **Number** & **\%** \\ \hline Descriptive (dfe) & 55 & 98.2 & umd & 21 & 37.5 \\  & & & pmd & 34 & 60.7 \\ \hline \multirow{2}{*}{Attitudinal (afe)} & 1 & \(1.8\) & emv & 1 & 1.8 \\  & & & ntl & 0 & 0 \\ \hline \multicolumn{6}{c}{(b) **Lab Experiment**} \\ \hline
**Feature** & **Number** & **\%** & **dfe/afe** & **Number** & **\%** \\ \hline Descriptive (dfe) & 96 & 98 & umd & 49 & 50 \\  & & & pmd & 47 & 48 \\ \hline \multirow{2}{*}{Attitudinal (afe)} & 2 & 2 & emv & 2 & 2 \\  & & & ntl & 0 & 0 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Distribution of attributes in different categories after VPA. ratio). These are clustered with the aforementioned perceptual sense of being surrounded by reverberation, thus suggesting that these physical properties might be associated with the perception of \"envelopment\". New attributes describing the direction of the early reflections and reverberation relative to the central axis were elicited (No. 9, 18, 54). It is considered that these attributes are results of testing multiple listening position and multiple head orientations. It is worth noting here that the scope of the present study was to define salient perceptual attributes for different listener positions and head orientations. This study is the first step towards the establishment of a cause-and-effect relationship between low-level and high-level attributes, which will be investigated in a future quantitative study. Additionally, cluster analysis could be performed on the different variables, in this case the listening positions and head orientations used as stimuli. Four clusters could be observed (Figure 11) showing similarities between different listening positions. Cluster 1 brings together P1_0\({}^{\circ}\), P1_90\({}^{\circ}\) and P1_180\({}^{\circ}\), the closest positions to the sound source. Cluster 2.1 showed a similarity between P2_90\({}^{\circ}\), P3_90\({}^{\circ}\) and P4_90\({}^{\circ}\). This is particularly interesting, as these positions are all facing 90\({}^{\circ}\) from the source. P3_0\({}^{\circ}\) and P4_0\({}^{\circ}\) can be observed in cluster 2.2 and they represent the two positions facing towards the source, but from on and off-centre listening position.