Excellant write up Zanth!
I have found the GS1000s can show signs of sibilance,but its usually a software(recording) issue.They are a very revealing Headphone.
Having spent a couple of weeks with The Grado prototype balanced amp & balanced GS1000s John had sent me to Beta test(Great synergy together )
in my system.I have to say I could live with this combo as my only setup with my EMM labs gear. The Gs1000s are very source dependent( they can sound like crap or just bring it all together to sonic bliss).
The last NY meet I had the setup hooked up to the EMM labs gear early on blew Stevesurfs mind listening to Diana Krall SACD.
The gs1000s,grado amp later got switched to the Leonardo CDP as a source for the combo & didn't fair as Well (To bad as others at the meet who listened to the combo with the leonardo & missed hearing the combo with the Emm Labs gear missed out on What I had been enjoying for the prior 3 weeks). I sent the combo back to John (didn't Really want to) I made some recomendations for dual volume controls & dual power supplies for the balanced amp,lets see if John incorporates them in the production unit.
I still have the prototype GS1000s from the national meet (They are mine & not going back ,unless I decide to go balanced when John comes out with the production balanced amp,then I will have them recabled).
I can listen to the GS1000s for hours as well,most comfortable Grado yet.