While active noise cancellation is only good at reducing continuous reoccurring sound, noise isolation reduces all sounds. Active noise cancellation is good at reducing noise from the air-con and airplanes. Noise Isolation reduces noise from screaming kids, dogs barking, wife/husband yelling, airplanes, speeding cars, drunken sailors, neighbors playing basketball. Just about everything. Best thing is, that great noise isolation has increased battery time versus active noise cancellation.