[jdenn]

Hi all, My work has decided that noise cancelling headphones aren't allowed. They believe that the 'microphone' in it records and is against the rules of the lab I work in. I was using a pair of Bose QC25. They may reverse their decision and let me bring it back in. 
 
So what I am after is something on the cheaper side (about $100 or under) that is closed back over the ear and I can wear about 8 hours a day.
Comfort and passive noise cancelling are my primary concerns, sound quality is a back seat as long as it isn't muddy since I stream my music at work)
 
 
THanks!

 

[cel4145]

Innerfidelity measures many headphones, and one of the measurements is there passive noise isolation:
http://www.innerfidelity.com/headphone-measurements

So you could look for models that they have measured. Note that you will want to look in the Full-Size Sealed Headphones category as open headphones are terrible at isolation.

 

[faultfracture]

Best isolating full size I've used is the Philips Crash by O'Neill. Styling is odd but they sound okay (bass heavy) and are dirt cheap.