High frequencies are passively attenuated by the foam inside the earcups. It's the mid frequencies (speech, etc.) that survive both active and passive noise ca

High frequencies are passively attenuated by the foam inside the earcups. It's the mid frequencies (speech, etc.) that survive both active and passive noise cancellation. Still, a high end pair of ANC headphones does a good job on speech/tv if you have some soft music playing through them.