One of the other members also mentioned encoding at higher bit rates a couple of weeks ago. (I use standard 128 Kbits but can go up to 320.) Anyway, I experimented with it at higher rate settings. What I seemed to notice mostly was that the higher the bit rate, the more diffuse and spacey the sound got. Then I found a technical article saying that (similar to the parallel MHz frequency issue) the human ear really cannot detect a discernable difference over 128K. That is, the benefit of the higher rates are lost on our feeble ears. So the other member started researching it too, and even found an online test where one can try to guess the rates, order them, and submit them for scoring. Turns out everyone flunks, because it's beyond the capacity of human hearing to accurately judge.
The thing that frustrates me though is that I have a recorder that in addition to WAV does DSD (Direct Stream Digital) at 1-bit/5.6MHz digital recordings. Problem is that I've yet to find an MP3 converter program that even knows what DSD (or a DFF file) is, never mind how to convert it! So I record in WAV, but as you know all too well, MP3 does rob fidelity unmercifully. I do understand that PianoStreet wants compression to save server space, but there's a self-defeating side to that too--the lower quality of recordings.