Have a look on ebay or the like, you should find something that will fit the bill. You could try Customcans , they will make you up a cable in any length you require and they aren't too pricey unlike some.A common ailment I believe. The lead with my HD 650s is just 3 metres, a tad short to reach my listening spot. Do Sennheiser do a longer one? Saw that Grado do an extension lead, but that's 4.5M itself, which might result in too much messy cable lying around.
I've been using the Grado extension for more than 15 years, previously with Grados and now with Neumanns. Just coil the excess. High quality, no added noise.A common ailment I believe. The lead with my HD 650s is just 3 metres, a tad short to reach my listening spot. Do Sennheiser do a longer one? Saw that Grado do an extension lead, but that's 4.5M itself, which might result in too much messy cable lying around.