the classification performance for all genres has improved jazz and metal are even at almost auc and indeedthe confusion matrix in the following plot also looks much better now we can clearly see the diagonal showing that the classifier manages to classify the genres correctly in most of the cases this classifier is actually quite usable to solve our initial taskif we would want to improve on thisthis confusion matrix quickly tells us where to focus onthe non-white spots on the non-diagonal places for instancewe have darker spot where we mislabel jazz songs as being rock with considerable probability to fix thiswe would probably need to dive deeper into the songs and extract thingsfor instancedrum patterns and similar genre-specific characteristics alsowhile glancing over the ismir papersyou may have also read about socalled auditory filterbank temporal envelope (aftefeatureswhich seem to outperform the mfcc features in certain situations maybe we should have look at them as wellthe nice thing is that being equipped with only roc curves and confusion matriceswe are free to pull in other expertsknowledge in terms of feature extractorswithout requiring ourselves to fully understand their inner workings our measurement tools will always tell us when the direction is right and when to change it of coursebeing machine learner who is eager to learnwe will always have the dim feeling that there is an exciting algorithm buried somewhere in black box of our feature extractorswhich is just waiting for us to be understood