They have a great bass for my iPhone. I'm very picky when it comes to headphones, and for me to give these headphones such high praise is out of the norm for me. I've head Beats by Dre, Sony, Apple, shoot you name it, I've had it. I listen to slot of justin bieber as well so I like to hear the boom & vocals. These headphones give a great boost to any song, and it cancels out all other outside sounds such as people talking, babies crying, or any other blasting music. Sound Quality I give this a 9 because all headphone sounds can be improved, and although this product is already pretty good, it can be improved in the sound. Comfort They offer different bud sizes so they fit in whateve size ears. They felt exceedingly comfortable in my ears, I can wear these headphones anywhere. Design I don't really like the cord because it's very thin & with a thin cord comes a sensitive wiring and with a sensitive wiring comes the greater chance of your headphones to stop working.