```r
# plot the spectral slices
ggplot(sS.dftlong) +
  aes(x = freq, y = track_value,col=labels) +
  geom_line() +
  facet_wrap( ~ sl_rowIdx + labels)
```

<img src="SpectralAnalysis_files/figure-html/unnamed-chunk-10-1.png" width="960" style="display: block; margin: auto;" />