The default clock rate is 21477272 Hz like the NES. Increasing it will sharpen the pitch, decreasing it will flatten the pitch. It's a linear scale. Doubling it goes up an octave, halving it down an octave, 3/2 up a perfect fifth, 9/8 a whole tone, etc.
The PAL one should correspond to 26601712 Hz but I had to work around the internal division by 12 which is assumed at a lot of places by NSFPlay, so the default value there is 26601712 * 12 / 16 = 19951284. Multiply that by the same ratio you multiply the NTSC clock by.
Before you consider altering the clock speed, though, have you tried different samplerates? Maybe your card has a problem with the one you've got selected. Open up the config page, there's a combo box at the top (takes effect when you start a new song). (Or you can type custom ones into the .ini file.)
I tried changing the NES_BASECYCLES in the in_vansf.ini file. I'm still confused on how the numbers work though lol. I changed it to 21677272 and it sounds just how I want it.
Thanks!
