Why buzzing noise sound the bass string of the upright piano.

[themaximillyan]

Very often situations arise when one of the 2 strings of one piano key makes a buzzing noise. Why is this happening here? Is it possible to fix this?
Unfortunately, when a copper bass string winding is lost, there is no way to fix it there. We need to remove this string from the upright piano. Replacing it on the identical string there. If the cross-section of the copper wire (diameter) is larger than on the broken string one, or the number of the coils is different than on the broken one, then its sound may differ there.
OR Try it way fix:
Piano Techs Fix: Before replacement of the buzzing bass wire a repair can be attempted as follows: With a tuning hammer loosen the offending wires tuning pin until the coil around the pin expands slightly. (don't break the coil) This takes the pitch of the wire way down and loosens it down to the hitch pin. With needle nose pliers remove the wires looped end from the hitch pin down below, and in turn the bridge pins, touch only the loop with the pliers. Insert a small screwdriver blade or an awl through the loop. Twist the wire twice or three times around in the same direction as the coper winding is wrapped around the steel core. Grab the loop with the needle nosers, remove the screw driver while holding the loop tightly and slip the loop back on to the hitch pin. Work the wire back onto the bridge pins in the same original position. Bring the string back up to pitch with the tuning hammer and tune the unison. This method can eliminate the buzzing as it tightens the copper coil around the steel core of the wire. If it does not eliminate the buzz replace the wire with a new duplicate made by a wire company. (Mapes or Arledge).