Curious for an opinion, or two, please. One of the BG midrange ribbons in my 201 buzzes/distorts on certain musical passages - but it does not appear to do it along the entire length, just at the top part of the ribbon. I can detect no breaks in the trace lines, nor any kind of other physical damage. I recall reading a long time ago that these ribbons can become 'loose' and require restretching; or that they can loosen due to higher humidity? May be completely untrue, dunno. Would appreciate any insights. Thanks!