Solution for high performance headphones that can run well on a modest headphone signal

I found the Sennheiser PX-200 headphones an ideal solution to a difficult problem of matching a high performance headphone capable of high volumes with good noise isolation, to a low signal power output as found coming from most portable music players and especially in my case from the headphone output on my sound card on my PC. The 115 dB SPL sound sensitivity of this headphone is extraordinarily high making the most out of low signal inputs. I have full size Sennheisers that of course have better bass at lower volumes but they drive me nuts because they can't be played loud enough for me without severe clipping heard on the bass. Also they were hot and heavy to wear. Ear bud headphones also provide high quality sound and even better sensitivity for very high volumes but they keep popping out of my ears and are especially uncomfortable needless to mention the ear wax mess. Contrastingly these headphones are extremely light and much more comfortable to wear especially for extended periods of time. The bass from this unit is punchy though not powerful when properly placed on one ears. After all one has to consider the size of the drivers. If the drivers were larger I'm sure the headphones would not play as loud as these and would weigh more. As is these headphones saved me from buying a headphone amplifier. The PX-200 headphones sound darn good with a modest bass boost on my CD player, or through tweaking with my PC sound card software. Lastly, the closed design is good for applications where the headphone is being used around other people for quality loud sound performance without complaints about leaking sound from nearby bystanders.