So I recently decided to downgrade my setup to free up some cash. Previously I was using a HD650 with the o2odac combo. I picked up a set of hd558 and a xonar dg to replace it. So here is what I did...
I fist removed the foam from the hd558. This significantly improved the airiness and noticeably improved the imaging. I assume the foam was leading to some reflections and was muddying things up a little. Needless to say I was thoroughly impressed with these cans. I found I was enjoying it far more than I ever enjoyed my HD650s, everything was clean, clear, with a definite space around sound stage elements in many recordings. I could pinpoint exactly where everything was in a 3d space, there was well defined depth, height and width separation. I was amazed! This was all out of the xonar dg, which was set to hifi mode to bypass the DSPs.
Next, curiosity hit me and I tried my hd650s again with the o2odac, and the sound stage was closed in and fuzzy. Instrument separation was difficult to distinguish. It sounded like **** but that beautiful tone was still intact. I assume that is just they way they are. When I tried my hd558 out of the o2odac they didn't sound the same as before. The separation and imaging was still better than the hd650s but not as clean and crisp as out the xonar dg. I tried it at varying volumes and no improvement. Normally I can't tell the difference between an amp and plugging my headphones into a light socket, but there is an obvious difference here. So I am trying to understand what has happened here. Based on the measurements the o2odac is theoretically perfect relative to human listening ability. So either two things happened:
1. The o2odac is broken
2. The xonar dg is accentuating certain frequencies and creating the illusion of clarity and improved imaging?
I posted this in the sound science forum because I figure I would get a straight answer or at least theories here, instead of the ******** and amp recommendations that I would be showered with anywhere else.
Thank you for taking the time to read this.
Edited by muad - 3/2/14 at 8:50pm