Hi, I’m seeking some help and advice in choosing an upgrade to my Sennheiser 598’s. One problem I have is that there are hardly any specialist retailers near where I live ( Cornwall, UK ) so I’m mostly ‘flying blind’. I am interested in a home setup ( I mostly listen to audio books on my iPhone and I’m happy with my Digital Silence DS 101A in-ears ). Most of my listening is via my MacBook with a HRT Microstreamer DAC/Amp, using the Fidelia player. I also use my hifi for listening about a third of the time ( Marantz CD 6003, NAD C 350 amplifier ). My musical tastes are predominantly jazz with some blues, soul and rock on occasion. The Sennheiser’s are perfectly acceptable but I find myself wondering if there is anything out there that would be a marked improvement given my setup. The price point I’m considering is around £250 ($375). I guess the key word is ‘marked’. I’m not really interested in an upgrade that would give me only a marginal improvement on the Sennheiser’s. From browsing this great site I have earmarked (sic) the PSB M4U2’s and the Focal Spirit Pro’s but I am very open to other suggestions. In general, I think I prefer closed back headphones. I’m hoping that someone in the community has experience of some of my potential choices and can give me some valuable advice.