Try running the SR225 unamped. My experience has been that by itself it already sounds pretty good, sometimes I prefer it to running it off my meta42. Also the bowl pads are good for soundstage, but if you want more bass, try the yellow Senn pads, or the flat pads. The reason bass sounds very lacking is because the drivers are so far away from your head with the bowls. The difference is quite noticeable.
If you want detail AND bass, try the older Joe Grado SR100, and most likely the SR200 as well, although bear in mind that I haven't heard the SR200's yet, so it's purely speculation on my part.
So far I keep coming back to the SR100...