Noise cancellation for known sources Creating a noise cancelling earphones that cancel/suppress speech is a huge challenge , maybe even impossible. 

But what happens if we change the goals a bit:


We need to cancel the noise(music,speech) coming from a tv in the same room. 
We can receive what audio the tv will create , some time before it's created through the speaker. 


Does it make it possible to create great noise cancellation ? how would it work ?
If you have audio that will be played by TV beforehand, then this problem becomes almost similar to echo cancellation, i.e. adaptive filters could be used and cancellation will be great.

What we have is the audio that will be played through TV, this audio will be used as reference for adaptive filter and input to the adaptive filter would be the capture(noisy music in earphone/headphone).
so adaptive filter will try to estimate the TV's audio in the earphone capture, then this estimate could be subtracted from earphone capture to get noise free(TV noise) music in earphone/headphone.