So I chose to buy the AKG 450, however I saw a review that said these headphones should be listened with a 320kpbs and my music is only 256. Will it really be a big deal? Would buying a portable amp for it fix it? I also listen to classical. Also, what amp should I buy? I am looking for under $70 I thought about the Fiios E11. Any other reccomendations? Please help!