There's nothing like a weasel sticking his nose in where it might not belong... I've owned a number of Sennheiser headphones, and have never had a complaint about their sound. Sennheisers are the best headphones using conventional drivers (not planar-magnetic or electrostatic). My problem has been they just aren't very reliable. The connectors often come loose (I had to practically blackmail Sennheiser to fix that problem, which many owners had), and the internal wiring of the drivers of anothr pair broke, for no obvious reason. I'm curious to hear what the purchasers of these (and other) Sennheiser headphones have to say about their reliability.
GrizzledGeezerReliability is great, Warranty is good, replacement head pads and headband cushion can be found easily is a big plus. Sen sells millions of headphones and QC issues are not common, some people are just unlucky and search the issue and find a few others with the same issue, it's an electronic and sometimes they fail with all products. 3-4 years with my HD650 and around 7? with my HD600 have been nothing but perfect, paint seems to be the only issue and headband cracking if you're rough with them. I hear many more complains with other expensive brands and have issues with a few planars I've owned.
GrizzledGeezerI've had a pair of HD555's for about ten years and they are still going strong. Some paint wear, sure, and I finally replaced the pads last week. I'm very much looking forward to my HD6XX.
GrizzledGeezerI have had a pair of Sennheiser HD 565 for 19 years, HD 598 for 3 years and never had to replace a cable or spare part bar a headband cushion and earpads.