Roger Waring was wondering about the buzzing sound in a piano which stops
when he lifts four or five strings off the bridge.  I didn't understand
how he could tune it up again that way to hear the difference, but I
would suggest a few other repairs that might be considered for buzzes in
a piano.

In the letter before he had isolated the buzz to a particular soundboard
rib.  But these buzzes can be just about anywhere.  I have spent
uncounted hours looking for sympathetic buzzes, and after being positive
they were in my soundboard or in the cap on my bridge, I would finally
locate them.  One buzz was in a fully restored Ampico, behind the plate's
wooden cover strip mounted to the top stringer that spans the width of
the piano.  It was as loud as a soundboard buzz, and always on one or two
notes.

A number of times you will finally locate one between the piano action
tray and the keybed of a Marshall & Wendell, because the action tray is
not fitted with dome slides for a solid point seat.  Instead, the factory
used veneer scrap to shim out the wobble and to level it.  Not being able
to shim accurately that way, the tray often buzzed.  The name-board will
also buzz sometimes, particularly if it rests on wood instead of felt.
And any loose veneer is also a candidate.  Try this one: A new, soft felt
pad rest for a name-board, and yet the name-board still buzzes.  There was
no loose veneer at all-- on the name-board.  But the poplar veneer the
felt was glued to wasn't perfectly tight, apparently.

At any rate, once you've been appropriately scared to death, most buzzes
are either in the soundboard or the bridge.  The bridges are capped and
the cap is glued, like a veneer, down to the bridge body.  The whole
thing is sanded.  Then the cap is painted, template drilled, and then
shaped with a chisel.  The work done to the assembly after it's glued up
(like the hammering) can sometimes pop it loose, but nobody knows about
it for years.  Then after the piano has undergone a restoration and
refinished, that's when the voids show up.  Injecting glue under the cap
usually does it.

As a matter of fact, if the pins are loose, often sections of the cap
are, too.  So if you will press some Devcon 5 -minute clear epoxy into
those pin holes and then reinsert the pins, wiping off the excess, of
course, as you drive them into the wet and slightly warmed epoxy (which
makes it very thin), they create a pressure that forces that epoxy
throughout every crack and void under the cap and in the body of the
bridge.  That always fixes a loose cap.

Remember, buzzes cannot be seen.  Cracks that are large enough to notice
cannot buzz, usually, because it would take too great a concentration of
energy, and their resonance would be very low, anyway.

As for lifting strings as a method of finding a buzz, all I can say is,
any change that you make in the pressure is apt to stop the buzz  if it
is on a bridge or in a soundboard.  Just pressing down on the bridge will
stop a buzz in the soundboard two feet away, sometimes.  You can press
here and there and actually stop a sympathetic vibration which is, in
reality, not even connected to the part you are pressing on! Finding
buzzes can be a real art, and can consume more time than it took to
string the piano in the first place!  So good luck.

Craig Brougher