Suddenly defective

I bought the headphones because the product description sounds as if these headphones change my life;) Anyway, you get the feeling to buy a product with a great price-performance ratio and Philips is finally also a well-known manufacturers.
First, the headphones were pretty good, have with me a little depressed in the ear after prolonged use. I also had the impression that they better hide outside noise as my last pair.
Despite moderate use came after 3 or 4 months of the moment when I connect the headphones to my ipod in one ear and I heard the music much quieter and darker. That extremely annoyed, so I use my old transitional headphones. I have no idea where it comes from. The headphones have not become wet and loose or torn out on the cables are not visible. Pretty disappointing and actually I did not want to search again for headphones.
Conclusion: Maybe I just had bad luck, but I would no longer recommend it.