I feel like I really oughta know the answer to this, but since I rarely do full start-to-finish setups on my instruments I want to double-check before I dive in. I've got a fretless bass where the action is remarkably low. Like, too low to work comfortably for my technique. If I pluck very gently it sounds wonderful, but as soon as I dig in with any force -- say, trying to play mezzoforte or louder -- the strings buzz/rattle conspicuously against the fingerboard. And it does this consistently at every position on the neck, on every string. It's not "mwah", it's "clank". So my question: Do I alleviate this buzzing/rattling by loosening the trussrod (to create more relief), or by increasing the height of the bridge saddles (to raise the action) ...or both? Thanks.