For heart sounds listen to the synthetic sound while reviewing this lesson.
When a patient whispers '1-2-3', the voice high frequencies, or soft vowel sounds are dampened in a normal lung.
Ask the patient to whisper '1-2-3' several times while auscultating the chest walls. Over healthy lung areas, '1-2-3' is not intelligible.
Compare this sound to the recording found in the "Whispered Pectoriloquy - Abnormal" lesson.