That's the key trade-off between the RS1i and PS1000, on tracks where you want to be closer to those euphoric highs - the RS1i is more intimate but also
more 'shouty' through the upper mids and treble on occasion, you find yourself having to occasionally regulate the volume as you chase that perfect volume level.
The PS1000 is extremely smooth due to the pad separation between the ear and driver, almost to the point that as mentioned in some other post -
you can find yourself listening at very loud SPL's with acceptable levels of comfort and yet be totally aware that your hearing is not going to last if
you continue to do so!
Treble summary in other words - the RS1i is more immediate sounding but the PS1000 presents a more realistic, live type of high note that is quite
inviting but it can beckon you to keep upping the volume - this is a very crucial point to consider with these - it sounds very pleasant, far beyond
where other cans have started to sound harsh and you automatically reduce the volume, the PS1000 still sounds great at silly SPL's so be careful.
Comfort wise it's another mixed bag - the PS1000 is a dedicated 'sit down and stay put' headphone like the HD800 LCD2/LCD3 - yes it's big and heavy
but it's quite balanced once placed on the head, the pads act as support mechanisms from the side. The only downfall is that after a few hours you
will notice where the main load is acting on your head. Usually a small 3cm x 3cm contact patch atop of your head starts to feel the weight.
I'm yet to finalize the solution myself but it's not a deal breaker - they just need a clever $60-$100 custom 'clip-on' custom headband to distribute
the weight to outer edges of the head and add further support.
By comparison, the RS1i is ridiculously light and handy - especially for a headphone capable of this sort of reproduction quality, but I do find
it clamps a little (yet to bend the headband from the stock position) more than my 325i.
Thanks again Gwarmi. I appreciate your thoughtful replies.