HE-500 is smoother, yes. I actually found the T1 to be too bright and wasn’t as impressed with the imaging and separation as I am with the HE-500. I know you’re a big fan of it but it’s not to everyone’s taste as it has a little too much brightness for some.
Either one is good but the HE-500 hits a nice sweet spot. not too bright, not too dark.and excellent technical capabilities
T1 or HD800 needs an expensive tube amps to tame the brightness--IMO
Als, they are very good headphones