daveross

More info - I found that the sample rate shift doesn't occur in iTunes, but always in Foobar, JRiver, and Media Player. Actually, in Media Player, the sample rate change also occurs when I stop playblack (click the stop button). Does this suggest anything? And...the results are the same whether I use ASIO or whether I avoid ASIO and just un-map the Proton from KMIXER in Audio Device properties. By the way, thank you all for trying to help with this.

Gordon, I just checked out the Proton on the IBM (which is running XP Pro SP2). I get the same results with uncompressed .wav and .flac files: the sample rate indicator jumps to 96k at the beginning of a 44.1 file and then returns to 44.1k. The audio transient seems to be associated with the jump to 96k.

Lars, thanks for the ASIO2K suggestion. Unfortunately, it still supports only 16 bit audio. Just to try it, I installed it anyway and found that it doesn't show up in Foobar. And even if I simply assign ASIO2K to the Proton and select no ASIO driver in Foobar, the result is still the same. Perhaps more importantly, I just noticed something I didn't notice before: When playing a 44.1/16 file, the Proton's sample rate indicator jumps to 96 and then returns to 44.1 (even when the previous file was also a 44.1/16 file). The indicator jump lines up with the transient I hear at the beginning of each file.

Thanks very much for the suggestions but no luck so far. First, I tried updating the driver but after searching Windows Update, Windows said the driver is current. I also tried the KS extension for Foobar but that doesn't work at all (files don't even play).

Gordon, thank you for posting this. Let me clarify one aspect of the post: the (sometimes loud) transient click occurs at the beginning of every file, regardless of the sampling or bit rate (if I stop (but not pause) a file that's playing, I hear the transient when I press play again). The noise is not at all associated with a change in sample rates between consecutive files.