Join Date: Jan 2009
Location: Canadian in Cambridge, MA
Re: Half step down tunning, does it need truss rod adjustment?
Try to get a measurement of neck relief with a set of feeler gages, or sheets of paper. If the neck relief gets too small, you need to losen the truss rod. I can't think of a good reference, but I believe it's best to adjust the truss rod without string tension.
For me, seasonal truss rod adjustments are 1/8" of a turn at most, and usually when the humidity goes low in the winter, then when the humidity comes back in spring.