This seems to be a pretty common problem with external recorders. While cameras seem to have no difficulty recording audio at a constant and correct rate, not only across models but even across brands, audio devices vary all over the place in their timings, such that they have to be retimed in post. Mine was off by a fairly constant .04%. Changing the speed of the audio by that amount allowed it to stay in sync over long runs. You'll have to experiment to find out what percentage works for you.
↧