I expected the dual dynamic driver to provide a good slam in the lower frequencies and I wasn?t disappointed. I was scared to purchase it but I said screw it and did it and Im glad I did. I wear a size 36B and most of the time a small size sports bra fits perfect, the way I like. I wanted some plastic shoes that could get wet and not fall off like flip flops. Now, these are not the earphones to use in depicting the amazing musical soundstage while listening to the hearing the click/s in the Zulu language on the Lion King soundtrack, ?Circle of life? by musician Lebo M or the sounds of the flute and the whistling soloist in the performance of ?The good, the bad and the ugly? by the Danish National Symphony Orchestra. I gotta say that I really love this phone. Been using this system for several years as a police officer outside on patrol. I have other Birkenstock?s and these are not similar in quality, design or fit. That keeps it from overwhelming the midrange and treble as much as in Extra Bass mode. The material/cut seems forgiving and maybe even flattering.