## 2 Materials and Methods
### Musicological Analysis of Novel Events  
Due to relatively high MIR feature levels and change rates in the metal rock and modern symphony orchestra music pieces, the automatic MIR approach identified too few acoustical feature-peak events satisfying the second criteria (the PLIP criteria), which might compromise the possibility of obtaining neural correlates of the acoustical feature processing. Hence, we also decided to introduce a musicological analysis of the pieces, which was conducted by the first author, to investigate the possible effects of novelty in the music structure. The metal rock piece _SC_ begins with a repetitive and quiet guitar solo consisting of an 8-note figure repeated 8 times. Every second 8-note figure is played on a C-minor-6 and Bb-major-7 chord. A quiet C pitch is played on the bas and fades out during the first 4 repetitions of the guitar figure. This is followed by drums, bas, guitar and keyboard playing an expected C-minor chord, but with a novel high loudness level and distortion effects added (Figure 1, top). The excerpt of the modern symphony orchestra piece _RS_ starts with an introduction part for woodwind instruments, consisting of phrases alternating between major-minor mode tonalities and harmonic progressions of unclear tonality (music score measures 1-75). The following 'Augurs of Spring' part begins with the novel 'Augurs' chord, which is commonly defined as atonal or as a polychord consisting of an E-major superposed on an Eb-major seventh chord (music score measure 76, \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Piece** & **Feature** & \(n\) **MoRI Peaks** & \(n\) **Time Points** & **PLIP (s.)** & **Distance to Prev. (s.)** \\ \hline \(AN\) (tango) & _RMS amplitude_ & 1773 & 10 & 1.502 & 14.710 \\  & & & & (1.009-5.604) & (9.574-94.563) \\ \hline \multirow{4}{*}{} & _Spectral flux_ & 3009 & 10 & 2.010 & 13.355 \\  & & & (1.27–5.601) & (7.932–130.003) \\ \hline \multirow{4}{*}{} & _Brightness_ & 2737 & 10 & 1.392 & 9.961 \\  & & & (1.069–4.635) & (5.917–41.248) \\ \hline \multirow{4}{*}{} & _Zero-crossing rate_ & 2628 & 10 & 1.810 & 11.219 \\  & & & (1.262–3.723) & (6.950–50.958) \\ \hline \multirow{4}{*}{} & _Roughness_ & 2649 & 10 & 4.747 & 25.715 \\  & & & (1.056–32.270) & (10.576–93.774) \\ \hline \multirow{4}{*}{} & _SC_ & & 1.139 & 7.869 \\  & & & (1.009–14.782) & (5.105–91.639) \\ \hline \multirow{4}{*}{} & _Spectral flux_ & 3198 & 5 & 1.239 & 68.7329 \\  & & & (1.176–1.881) & (20.286–198.027) \\ \hline \multirow{4}{*}{} & _Brightness_ & 3172 & 0 & - & - \\  & & & & (1.079–2.814) & (4.675–84.237) \\ \hline \multirow{4}{*}{} & _Zero-crossing rate_ & 2884 & 10 & 1.313 & 22.206 \\  & & & (1.016–1.945) & (5.131–61.517) \\ \hline \multirow{4}{*}{} & _Roughness_ & 2820 & 10 & 4.494 & 24.102 \\  & & & (1.062–30.552) & (12.947–54.451) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Automatically extracted time points. The number of peaks in the music information retrieval (MIR) feature increases, \(n\) magnitude of rapid increase (MoRI) peaks, corresponds to the MIR feature increase peaks among the 30% highest of the MoRI values. The assumed best time points, \(n\) time points, are the number of automatically extracted time points. For the assumed best time points with feature increase evoking brain responses the median PLIP in seconds and distance to previous time points in seconds are shown with ranges in parenthesis. at rehearsal number 13) [40]. Although the chord is consistent with the chromatic tuning system of contemporary Western music, it is novel and presumably evokes a measurable novelty related brain response [17; 20], since it neither belongs to a typical harmonic progression in major or minor mode, nor adheres to a common major or minor mode pitch class [40] (e.g., see Figure 1, bottom). These two cases of novel events in the music structure were found among the full set of automatically detected MoRI peaks for both the loudness (RMS) and the spectral flux increases (see Section 2.4 and Table 1).