Here we have an example of a split bass bridge. This will create a buzzing noise as the bridge pins rattle against the strings. The strings are supposed to be staggered as they go through the pins  Notice the lines on the bridge that show where the strings used to be, and how the pins in the upper row have moved over to the right. To repair this requires making a new bridge cap.

When looking at a used piano, checking the state of the bridges is important. Repair of this is more expensive.