Thanks again for the replies, i've had a talk with dad and i think he is going to go for the ear defender and earphone combo like the Etymotic IEMs. thanks for your advice guys, much appreciated. 

Thanks for the replies but am unsure if the Bose QC15 and the Sennheiser PXC 450 will do the trick as the Bose noise reduction is only 17.5 dB, again the PXC 450 reduces up to 23 dB. obviously the headphone cups will reduce noise as well. The Ultraphone reduces noise by up to 29dB that sort of...

Hello all, hopefully someone can help me with my predicament. I am looking for specific noise cancellation headphones for my farther, but unfortunately i can't seem to find suitable ones.  He works away and has to travel in a c-17 globemaster which i believe inside is about 86 dB and i'm...