I have 6 outs on my headphone amp. Looking for a total of 6 headphones for my middle school recording studio. I think I want to get 2 pairs of the Vic Firth Isolation headphones. I am looking for 3 pairs of headphones for tracking, hopefully in the price range of 20 to 30 US dollars. Also, I need one pair for mixing, with a budget of 50-60. Any recommendations?