Have you guys been in noisy flights or vehicles (like trains)? You notice the high level of low frequency noise? Is active noise cancelling better at getting rid of most noise down to the lower frequencies or is just regular sound isolation just as good or even better? Sound isolation I understand seals from sound leakage/ingress, but even with the seal, there is the lower frequency air-plane noise. Can that be cancelled out as well with active noise-cancelling?