You guys are tough customers. I'm new to the whole electrostatic scene so take my impressions for what they are.
Rig: Cambridge Audio 840C > Parasound D/AC-1100HD > Stax SRM-1/MK-2 Professional > Stax SR-404 Limited Edition / Airbow SC-1
Preamble: Recently I became more curious about Electrostatics (and it's all your fault, all of you!). I had heard them briefly in meet conditions, and never really grasped their goodness. So I asked a friend if I could borrow his Airbow rig for some extended listening at home. This extended session impressed me enough to pursue a Stax rig. The sound was smooth and effortless and I could listen to it for hours. I decided to purchase the 404LE used, with very low hours, and hoped for the best. Happy with that decision, I then bought an SRM1/MK2.
Sound: Both headphones are obviously from the same family. The sound is similar with a "couple" salient differences. The 404LE is brighter than the SC1 and hence can sound less smooth and forgiving. The other side of the coin is that the LE is more transparent. The LE also has a bit more bass quantity and impact. Soundstage depth is also deeper on the LE but the difference is small.
Conclusion: If I wanted a headphone I could listen to all day the advantage would go to the Airbow SC-1. Technically, the SR-404LE is a better headphone. I would like to tone down the highs a bit with some damping, but that may cause other issues; hopefully, I will only have to give up a bit of transparency to gain some listening comfort during longer listening sessions.
