The AKG K 400s are a set of recording studio headphones best suited for playback and monitoring during recording.<span> </span>These are the type of headphones that you would wear to hear the rest of the mix or the rest of the players during recording, rather than for mixing or mastering.<span> </span>They simply lack the full dynamic range that you would need to have for a set of mixing headphones.<span> </span>They are build pretty decently, as AKG knows what they are doing when it comes to headphones since they have been making them for so many years.<span> </span>This being said, these definitely aren’t the sturdiest headphones that AKG has to offer, as they are somewhat flexible.<span> </span>This isn’t necessary a bad thing as the trade off is that they are pretty comfortable and easy to wear.<span> </span>Going back to the sound quality, don’t get me wrong as I think you’ll be able to hear everything pretty clearly, it’s just that they aren’t designed to project the frequency response that you would want for mixing or critical listening.<span> </span>I’m not too sure how much these would go for used, but I don’t think that they are all too expensive.<span> </span>Even when it comes down to simple monitoring and listening studio headphones, the K 400s wouldn’t be my first recommendation, but they will definitely get the job done.<span> </span>I’d recommend checking out some of the other headphones that AKG has to offer, as I believe that there are better made and better sounding headphones in the same price range that they have to offer.<span> </span>If you’re not looking for anything too fancy or anything that you can mix on and want a pair of headphones for musicians to listen back on in the studio, the AKG K 400s are worth a bit of research and investigation…