This problem is caused by the dampers getting old and a bit hard. Easy solution is to retime the dampers so 1/3 are ever so slightly faster and 1/3 are ever so slow, and the rest are unmoved. I am speaking of the thickness of a piece of paper difference and they are regulated so one is up, one unchanged one is down one is unchanged one is up, etc. A common practice in recording studios. Very very little change but it will make a difference. Newton
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