1. Vocal Technique: Stewart's vocal style involves a lot of belting and a unique rasp that he has cultivated over the years. He often uses his lower register and belts out powerful notes, which can strain his vocal cords and create a rough texture.
2. Vocal Cords: Stewart has naturally thick and robust vocal cords, which contributes to the raspiness of his voice. The thickness of his vocal cords allows him to produce a more resonant and powerful sound.
3. Aging and Wear: Stewart has been performing for several decades, and the natural aging process, combined with the rigors of touring and performing, can take a toll on the voice. Over time, vocal cords can become strained, and the voice can develop a rasp or hoarseness.
4. Lifestyle Factors: Smoking and excessive alcohol consumption can also affect the vocal cords and contribute to a raspy voice. Stewart has admitted to smoking and drinking in the past, which could have further contributed to the development of his raspy vocal tone.
It's important to note that Stewart's raspy voice is not necessarily a sign of vocal damage. Many singers develop a raspy or rough vocal tone as a stylistic choice or as a natural consequence of their vocal technique and vocal cords. In Stewart's case, his raspy voice has become a signature part of his vocal style and has contributed to his distinct sound.