I just recently bought px160 After reading almost every reviews online and watching all the demo videos on YouTube. It sounded amazing. Since I was going to okay the piano almost 100 percent of time with a good headphone, I thought it was not necessary to buy higher models that have better speaker system (believed that they all carry the same piano sound if heard using a headphone). Therefore, instead of investing money on piano, I spent them on the headphone Sennheiser HD598 with impedance of 50 ohm which (I believe) is enough to sound great on most portable devices. However, compared to Sony MDR-XB500 (which has heavy bass focus, so I do not like the sound from it), the sound quality I am getting from HD598 is muffled and very disappointing. Could someone figure out this kind of issue? Also, any advice to improve the sound quality of px160 heard from a headphone is greatly appreciated! I spent more than 200 dollars on the headphone thinking that it will make the px160 sound like a real piano...... The headphone works great on any other device. It is just with px160 that I am disappointed at....