## 4 Results
### Perception of Separateness and Roughness  
The mean perception over all subjects of separateness is shown in Figure 5, and the mean perception of roughness in Figure 6, sorted by the musical interval present in the sound. The familiar guitar sound subset includes all intervals, and to make this subset clearly visible the guitar tones are connected with the yellow line. Using a one-way ANOVA, the significance p-value was found to be \(3.7\times 10^{-46}\) for separateness perception and \(2.91\times 10^{-25}\) for roughness when comparing the subjects' judgement distributions of the 30 sound examples. The separateness perception shows nearly all unfamiliar sounds being perceived as less separated than the guitar sounds. This points to different perception strategies between these two subsets: familiar and unfamiliar sounds. The only exception is the'strings 2 octaves' sound, which is shown with its ISI histogram in Figure 2's middle plot. Here, the two notes are separated by over an octave and the ISI histogram shows two clearly distinguished peaks at the respective fundamental frequencies of the two notes in this sound sample. When discussing instrument families the _dutar_ and the _saung gauk_ are both plucked stringed instruments like the guitar. Both are lower than the guitar tones in terms of separateness perception. This also holds for the two strings sounds, which are also supposed to be familiar to Western listeners and which are also perceived more fused than separated. These sounds are artificial string pad sounds, which have already been discussed above as unfamiliar, insofar as such synth sounds can be produced with arbitrary synthesis methods and parameters, which make these sounds unpredictable, and therefore, unfamiliar to listeners too. The only sound which is still familiar would then be the piano, which is indeed close to the guitar sound in terms of separateness. The least separated sounds are the gongs and the _roneat deik_, which are percussion instruments in the sense of having inharmonic overtone spectra, although the _roneat deik_ is a pitched instrument. With the four instruments having a major seventh interval it is interesting to see how strong the influence of the instrument sound is in terms of separateness perception. Figure 5: Mean perception of separateness of all stimuli sorted according their musical interval (gongs are sorted as unisono). As the guitar tones form the familiar subgroup, and the guitar is the only instrument having all 13 intervals in the octave, they are connected with the yellow line. Except for the ‘strings 2 octaves’ sound, which is the string pad sound, whose ISI histogram is shown in Figure 2, all non-familiar sounds are perceived as well separated, and therefore, as more fused compared to the familiar guitar sound. This points to a different perception strategy for familiar and unfamiliar sounds. Furthermore, the guitar sounds show the least separateness in unisono and octave as expected, and most separateness with the major seventh. The roughness perception shown in Figure 6 does not show such a clear distinction between familiar and unfamiliar sounds. The guitar tones show a roughness perception as expected, least with the unisono, octave, fourth, and fifth, and strongest with the minor second, major seventh, and tritone. It is interesting to see that all four _hulusi_ sounds are above the guitar, so perceived as more rough, following the roughness perception of the guitar qualitatively (major seventh most rough, fifth least rough, etc.). The mean and standard deviations for roughness and separateness perception are also displayed in Table 2 for the guitar sound and in Table 3 for the unfamiliar sounds. Also, the gongs and the _roneat deik_ are perceived with low roughness, they were also perceived as low in separateness. Still, overall, no perception strategy similar to that found for separateness can be found for roughness.