The vocal folds are long , smooth , rounded bands of muscle tissue that can be lengthened or shortened , tense Relaxed , and separated or approximated . They are attached the thyroid cartilage in the front and to the arytenoid cartilage , causes the vocal folds to open wide during respiration or to close , tense , and stretch during phonation . For sound to be produced when exhaled air passes through the vocal folds , their edges must be more or less closed ; the amount of closing affects voice quality