SeanK1996I hope the k553's get along with devices better than the q701's; I can't listen to my q701's without running them through some pretty complex equalising (though I love them with it). The k550's (which the k553's should be similar to) look like they have reduced response in the 4-7k range compared to the q701's, which is part of what kills me with the q701's. Lower impedance should help with running off other sources too, though bad sources will still be bad sources =(
Comparison graph between the k550 and q701 here: http://graphs.headphone.com/graphCompare.php?graphType=0&graphID[]=3571&graphID[]=2931&scale=20
qpyungNah, totally different drivers, Q701 is 45mm, K553 is 50mm, and even besides from size they are engineered completely differently, Q701 is stiff driver, less sensitive, needs an amp, sounds more clinical. K553 is sensitive, doesn't need an amp, has better bass extension and a fuller sound. etc.