It is not an easy poll, as in case you want to be exact, you cannot choose only 1 thing to describe what makes Congolese music Congolese music. But i remember that when for me it comes to think about answering the question: "this song could be very good but there is definately something missing from it, what is it?", almost always I conclude it is a good animation. So the distinct Congolese sound is given by the solo and atalaku, but it seems to me there are less good atalakus than soloists.