Sennheiser MM50 for iPhone Headphones
My Sennheiser MM50 headphones have died. 
I haven’t had them all that long either — no more than 9 months.
Like others in this Whirlpool thread, the right channel of my headphones has stopped making sound. It’s super annoying to listen to stereo music with just the left channel.
Mind you, when the headphones are working properly and you have the correct size ear plugs fitted, these headphones sound great. If you think the bass is a bit tinny, try the next size ear plug — it will make an enormous difference.
Syntec International Pty Limited is a distributor of Sennheiser products here in Sydney. They have an Service and Spare Parts e-mail address which I’ll use.
This is very disappointing. Here in Oz, these headphones cost AU$130.00, so I’d expect them to last a lot longer than what they have. Thankfully, they have a two year guarantee, so a replacement set should be at no cost to me.