i was playing with the KEYS free Virsyn Micro Tera and by adding a few bars of harmonics in the 053-060 range to the preset steel bass, I got a terrific bass sound -- lots of punch, edge and growl.
i built a song around this and once i added some pads and strings and such and listened to it closely the bass sound is on pitch on strike, but any note held quarter or half value tends to go a little flat -- just like a real bass might go sharp on strike and come back to pitch on sustain.
i've tried adjusting fine tune: osc 2 and were detuned a few cents in offsetiing directions, and osc two was tuned +7, osc 3 -12. I've adjusted these and the growl changes, but not the flattened sustain.

so two questions:
what's going on here? and
any suggestions?

Haven't played with Micro Tera,but I'll bet you've either got 1)an envelope or a slow LFO still modulating the pitch somewhere,or 2)velocity modulating the pitch,and the whole patch is flat.I know I program basses a little flat and use velocity to bring the attack up to the proper pitch a lot myself
ew

thanks ew, but
well there's no modulation at all. i suspect it's the harmonic i threw in is the culprit. if it sustains even longer it comes back to pitch. i tried moving the harmonics around and changing levels, but finally i gave up and pulled an equally growly bass from Carbon.
not the first time i get inspired by a sound to build a song and then that sound doesn't make the final cut