The shape of the mouth changes the harmonic content of the sound in the same way it affects the harmonic content generated by the vocal folds when speaking .
The shape of the mouth filters the sound , with the modified sound being picked up by the microphone .
The shape of the mouth changes the harmonic content of the sound in the same way shape affects the harmonic content generated by the vocal folds when speaking .
The shape of the mouth filters the sound , with the modified sound being picked up by the microphone .