The earphones from Sony are outstanding when the pads used matches the ear canal. I have also had very expensive headphones from Sennheiser, but what make the Sony Headphones on sound volume does not even make a 100-EUR expensive pair of Sennheiser. Of course, the volume is due to the emphasis of the low frequencies, but exactly compensates for the shortcoming of many Sony products from its competitors. On I-Pod I've never heard better. But the importance of using the right pad. This should "seal" the ear canal properly otherwise it sounds empty and no better than at 5 EUR plugs.
