When I listen to a pro jazz player play, I'm frustrated to not be able to play with the control and evenness in time that they can do. As I listen to my own recordings, it's fraught with technical flaws.
I realize that this is the difficulty with jazz. I think I've gotten to a point now where I can play mostly with my ears and less with my fingers. And this means that sometimes the fingers end up in a position not conducive to a good tone. Or sometimes I get too excited thinking about the melodies coming out that I'm over-accenting. Or it gets out of time a little as I try to recover from some position to go to the next note.
It's the next big hurdle for me that makes me sound amateurish. I think that hearing these flaws is the beginning stages of my improvement here. I probably couldn't hear these much before.
I was asking my teacher this question and I actually had him listen to my jam session performance. To him it was all good. He said I could hear when I was going out of time and then I readjust. But when I hear a professional play, I don't hear this. So maybe they're just adjusting their time at a more frequent rate than me. This is jazz after all and we don't exactly know what we're going to play until we do it.
In the meantime I've realized that part of the culprit is my LH. Due to less technical development, it will tend to waver in time more and it affects the RH. Lately, I've been more focused on improving LH scales and listen more closely at a finer level. Also by practicing Walking bass I can pay more attention to the LH.
The other solution is to make my phrases shorter. Trying to play long lines like Keith Jarrett isn't going to help. I've known this for awhile. Frequent spaces in playing is not just "breathing" and syncopation. It's a chance to listen to reestablish the groove. I've been told this a zillion times. But maybe it's just sinking in now that the "listening" part has been missing.
Another thing I just recently discovered, and related to listening, is that to check my overall sound, I'm typically paying attention to the strike points in my playing. What I mean here is that I'm focused on the sound of my notes beginning. I'm noticing an improvement in my evenness if I listen to the length of the whole note playing. It changes my perception quite a bit. There's a masterclass on Youtube by Hal Galper here http://www.youtube.com/watch?v=JJRjEpjd9S4&feature=channel. At about 12:00 in, this is what I'm talking about.
Hopefully, my strong awareness of these problems will lead to a shorter term solution. The technique unfortunately takes time but maybe by listening and more frequently readjusting, it will be less obvious.