Re: Noise cancelling
For that I have the choice of a pair of plain Peltor 25dB hearing protectors, and a very similar pair with speakers built in.
As my Sennheiser is the venerable HD424 it won't do much[0] regarding blocking out unwanted sounds, the AKG K161 does quite a bit better there.
[0] balancing the headphone sound level with the speaker sound level you can get an amazing spacious soundscape. Especially nice with music like Tangerine Dream, Klaus Schulze and such.
Biting the hand that feeds IT
