like all Sennheiser headphone , the px100 be very comfortable . the pad press snugly against the ear and 2 small cushion rest on top of one 's head -lrb- in contrast to the loose-fitting Grado headphone , `` sr '' series -rrb- . the px100 's construction be a work of art , sennheiser obviously want they product to look beautiful . and they look better `` in person '' than they do online . for the price , they sound quite well . although the midrange frequency be a bit recessed , the bass be strong & well define and high frequency be very detail without sound aggressive or harsh . for example , on `` something I learn today , '' by Husker Du -lrb- Zen Arcade -rrb- , I can easily hear the last guitar note in the song quietly reverb -lrb- echo -rrb- 5 time as the song end . but when play thru the Sony mdr-7506 headphone -lrb- $ 100 -rrb- , I only hear a single guitar note , no reverb . and with a tiny , new battery-operated headphone amplifier I get on eBay for $ 65 , the pace & rhythm of music thru the px100 greatly improve and the midrange fill out a bit . -lrb- although the sensitivity of the px100 be quite high at 114db , the impedance be a low 32 ohm which may strain the power supplies of portable music source , affect sound quality . this be where a headphone amp that boost CURRENT can greatly help . but if you own headphone with high impedance , like the 300-ohm sennheiser hd-600 , you may need a headphone amp that boost VOLTAGE or the phone may play too quiet - even at full volume . for best result , the input impedance of headphone should be 10 time the output impedance of the music source . for example , if the owner 's manual of you portable music source list the output impedance as 15 ohm , you 'll get best result use headphone with a input impedance of 150 ohm . most people will never buy a head amp . but if you be a nerd like I and want perfection to you sound , you 'll need one if you phone ' impedance be not approximately 10x the output impedance of the music source . -rrb- on the downside , the px100 be very delicate and can easily break if handle roughly . the cover over the 2 cushion that rest on the head seem quite thin and may wear out sooner rather than later . and the cord be very thin , especially where it enter each phone . a firm tug on the wire could dislodge it from the phone . also , the hard plastic carry case have a spool to wrap the cord around when place inside . but over time , this flexing\/tugging of the cord by wrap on & off from spool will fatigue the thin wire , probably cause it to eventually break ; the cord may appear fine but you 'll have one of the phone go dead since the wire inside the plastic covering have break . -lrb- btw , most Sennheiser `` hd '' series headphone with the detachable cord will , within 1-2 year , have one or both of the phone cut out . replace the cord will not help as the problem be internal where the 2 plug make a electrical connection into each phone . I have a great-sounding $ 200 pair of hd-565 ovation headphone with this problem that could not be repair . throw they in the trash . what a waste ! avoid sennheiser with the detachable cord . -rrb- so ... 4 star for overall sound : 5 star for high frequency , 3 star for recessed midrange , and 4 star for bass which have a slight emphasis due to the recessed midrange . use the head amp easily bring the sound up to 5 star . however , the construction of the px100 be frail and the very thin cord will break unless you be super careful . but I be happy with the px100 . so far . -lrb- if you buy portable Sennheiser headphone be sure to buy from a authorized dealer since many be counterfeit fake , especially the sennheiser cx-300 earbud . Google for more info on this . -rrb-