Subglottal air pressure, airflow, and electromyographic activity of four intrinsic larygeal muscles were recorded during sustained phonation in the vocal-fry and low-frequency modal registers. Nine young adult males were subjects. In modal phonation there was greater airflow, greater cricothyroid and interarytenoid muscle activity, and decreased thyroarytenoid activity than in vocal fry. No differences were found between registers for subglottal air pressure or posterior cricoarytenoid muscle activity.