I bought these for my Sennheiser HD 201, after reading around on the forums that it can help with the lack of volume and bass. On the way home I used it with my iPhone 3G and Philips SHE3590. It helped the bass response and clarity of highs and mids, but for every text message that came (my country, the Philippines, is the texting capital of the world), whether on my phone or others, I can hear a loud static noise (sounds like "tut-trut-tut-trut"). If there is an incoming or outgoing call, it's even worse, sometimes incessant. Note to self: NEVER use...