Okay, I can't seem to get the intonation right on my bass. If I tune to a fretted note on all strings, all fretted notes will tune great, but the open notes are a little flat. So my strings will be in tune, but not when they're played open. I've messed with saddle positions and all that fun stuff, but nothing seems to work. Could it be bad placement of the nut, causing only open notes to be off?