The only grado I've ever owned was an SR60, which was a while ago, and I don't remember it. I've never heard a sony SAXXX. I don't like the kind of bass where you can HEAR all the low frequencys, but there is really no "thump" or "boom" to it. The KSC-75 seems to have more "thump" than the LTD, however the LTD is more detailed. I don't like the thumping to overpower the rest of the frequencys so everything else sounds muddy. It's hard to explain. What I would really like is bass that you can feel in your chest. I've heard that is true about the HD650, what about the 600 or 580? I certainly can't feel it on the LTD, or the KSC-75, but the KSC75 does have slightly more thump to it. I don't know the proper term. And unless anybody else has anything to say about amps, like the M3, I think I am leaning toward the headroom micro.