In a pinch, standard silicone earplugs work extremely well when you disregard the instructions and slowly push them deep inside your ear canal until you have a

In a pinch, standard silicone earplugs work extremely well when you disregard the instructions and slowly push them deep inside your ear canal until you have a perfect seal. With the Bose noise cancelling earphones, it's actually considered a feature that they don't block out conversational frequencies.