Thanks, everyone, for the responses. The feedback is greatly appreciated.   I think I'll enjoy the new Grados as they break in for a few months with the Pioneer receiver. I have to say that, after a bit more listening, I think the Pioneer/Grado combo sounds great. I'll take that time to learn...

Thanks, jonbmet, for the response.   I'm not overly conversant with reading amplifier specs. After perusing the Pioneer SC-67 manual, it would seem the amplifier has continuous average power output impedance of 4, 6, or 8ohms--depending on channel wattage. <shrug> Dammit, Jim, I'm a computer...

Thanks for the reply; however, the decision has already been made earlier today. My local shop gave me a decent price reduction on the RS1's that I was happy with (based in Internet comparisons), so I went ahead and bought them. So that part of the equation is completed!   Just now wondering...

Hello, all.   I just spent the weekend auditioning a pair of Grado RS1i's in my home. (My local dealer is awesome that way.) I liked them enough that I am planning to buy them without bothering, at this point in time, to audition my other possible choice (Senn HD650). The dealer is not sure...