Tone is usually made up of two parts, airflow and embouchure. There is still the matter of deciding your mouthpiece/reed combination that best suits you, but the player doesn't need that until he or she can establish good airflow, and a good embouchure. The tone of the clarinet has made it famous. Before the clarinet and even today there isn't an instrument with the dark and fluid sound of a clarinet. The tone of a clarinet depends nearly solely on what's going on at the top of the clarinet, i.e. is there a steady airstream going through the clarinet? Is the embouchure set correctly? Is there a good reed that's compatible with the mouthpiece and the player? Does the mouthpiece suit the player well? All of these questions are questions to ask when trying to create a good tone on the clarinet.