I know this has been up as a question some time ago but time moves on and maybe there are newer better options.
My Sennheiser CX300II have severely reduced volume in the left channel, no external reason apparent.
They`re only 18 months old so I may be able to get a replacement as Sennheiser offer a two year warranty.
If not what alternatives does anyone recommend as this is the third pair with a similar fault. They only ever seem to last about the warranty period or slightly longer.
Snaps
My new Flash Fiction blog. All my own work
500ish
I used to be with it, but then they changed what `it` was.
Now, what I`m with isn`t it, and what`s `it` seems weird and scary
SPEW ALERT
Mine worked perfectly for about four months then one earbud lost the sound. After a wee look it was apparent that ear wax was the problem 
I simply removed the rubber inserts and soaked the buds in very hot slightly soapy water for a few minutes whilst shaking the cord/buds vigorously. After that I spun them at the speed of sound by holding the jack in my hand while spinning them around which dries them perfectly. End result was perfect sound in each bud. Felt like spewing when I inspected the jar I cleaned them in and saw the shrapnel at the bottom of the jar 
Worth a try
Choagy FFCUK The SPL
I fear you`re skirting the real issue here choagy, the ear wax. What you require to do is as follows:
1) Park up the town, opposite Leckies` emporium would be ideal.
2) Fill ears with hot water.
3) Drive round the roundabout at the Post Office at ned in a Corsa velocity. Job done.
The wax will come fleein` oot due to centrifugal force and hearing will be restored and ear-phones will remain unclogged despite extended usage.
ps Make sure to apply clingfilm to the inside of car windows to make cleaning up after a dawdle. You can thank me later 
Forza Ferrari, Felipe & Fernando !!
Go Vale Go.....The Doctor....G.O.A.T. !!
Thanks Choagy.
Working earphones with the slight refinement of replacing centrifugal force with t`other halfs hair dryer.
Snaps
My new Flash Fiction blog. All my own work
500ish
I used to be with it, but then they changed what `it` was.
Now, what I`m with isn`t it, and what`s `it` seems weird and scary