I bought DX50 bundled with Westone 3 IEM's an year ago, mainly for "on the go" portable rig and I find myself quite satisfied with this kit. While trying to follow this thread eagerly since the beginning I just haven't had the chance to add my comments about DX50 yet, but I was thinking to share my experience then now. And my gratitude goes to all those contributors who have created, tested and provided feedback on different firmwares, bugs, mods here. It's a lot of help for all its users and it's cool to see so many enthusiasts around it! I'm sure I would have "bricked" my DAP long time ago without all those tips! :D
Now, year after release, there are so many different ways to make this piece of equipment to shine, but when thinking back, at the beginning I wasn't really happy with that player, especially with the sound color and synergy between those two - DAP and IEM's. It felt just too flat, or even too bright, and not giving enough punch on the bass side. And original FW with EQ's didn't help along either. I remember that every time new FW came out I was hoping for an improvement and it was kind of exciting to try them all out, it was somehow like a bonus on top of the original purchase :D It took a while until CW's started to bring some affect to EQ and sound signatures. Still, for me it didn't feel good/right enough, it felt more of a tease or an illusion. I mean those sound libraries were a real mess. Nobody had an exact picture what was changed there, or how EQ was supposed to work. Finally when Rockbox was ported to DX50 it gave an access to all sorts of tweaks and most importantly to EQ which was working at last! I have always loved the complexity and all those additional features that come with RB (already used it on my old DAP Cowon's X5), and this time as well I was really excited to try it out right away. RB is pretty much "transparent" itself, though its EQ and sound libraries are much more refined and mature which makes it easy to modify the sound to your taste. I found it perfectly suitable to my needs.
The sound difference in this case is noticed especially when swapping between W3 IEM's and pair of Denon AH-D2000's I use at home usually (attached to Audiotrak's DR.DAC3 preamp). Even when connecting D2000 straight to DX50 it has enough power and depth to run those cans. And that bass is a bliss with Rockbox! So clean and deep! In my eyes nothing can be compared to this, none of the CFW I have tried previously and I think I have tried them all (starting with DOC's versions plus now the Sound Unlocked). Yes, Sound Unlocked feels very neutral and all but it's not touching even the edge of the bass what RB can deliver. DX50 & RB combo goes even better when running through DR.DAC3, which adds wider impact to bass from its side as well. So in my eyes I think I have found this perfect combination and don't think I will be updating my player any time soon - rockbox is there to stay.
Like they say: "If it ain't broke, don't fix it" :)