I have a Sennheiser HD600 which I'm very fond of and drive them with an O2+ODAC combo at home and a DYI valve DAC/Amp combo I bought from Ebay a long time ago but which has a GREAT sound (after I spent as much for its hum suppressing power source lol).
Today for the first time I brought the HD600 + the valve DAC at my office where I work in an terrible noisy open space to concentrate with music to write an important document.
It worked well for me LOL but after a little time a coworker tapped on my shoulder and asked if I could lower the volume, much to my surprise, but actually have to say there's a lot of my music leaking out of my beloved cans :-) Guess that's why you call them open, right ? :-)
With a budget <= 300 what would you recommend for a similar sound but isolating me from the environment, and the environment from my music plus being very comfortable to wear (I strongly dislike in-ear).
I mainly listen to good recordings of Jazz and Classical and a lot of "world music".
Thanks for any opinion.